Table 2: Guidelines on questionnaire design and implementation.

First category	Second Category	Electronic Questionnaire	Email Questionnaire	Web Questionnaire	App Questionnaire
Survey’s Development	Item definition	Generate items through literature review, interviews, focus-group sessions, with potential respondents or experts. [3, 9] Create a “table of specification”, to ensure that sufficient items have been generated. [9] Develop the study to further implement best practices. [9] Insert items consistent with the aim of the survey. Unnecessary items can affect data quality.	Generate items through literature review, interviews, focus-group sessions, with potential respondents or experts. [10] Create a “table of specification”, to ensure that sufficient items have been generated. [9] Develop the study to further implement best practices. [9] Insert items consistent to the aim of the survey. Unnecessary items can affect data quality.	Generate items through literature review, interviews, focus-group sessions, with potential respondents or experts. [10] Create a “table of specification”, to ensure that sufficient items have been generated. [9] Develop the study to further implement best practices. [9] Insert items consistent to the aim of the survey. Unnecessary items can affect data quality.	Generate items through literature review, interviews, focus-group sessions, with potential respondents or experts. [10] Create a “table of specification”, to ensure that sufficient items have been generated. [9] Develop the study to further implement best practices. [9] Insert items consistent to the aim of the survey. Unnecessary items can affect data quality.
	Sample selection	To not have a self-selected group, non-probability sampling should meet the condition of sufficient response rate. [10] Direct effort at decreasing the occurrence of sampling measurement and non-response errors. [5] Bias must be avoided, both in the selection of the population being studied and in the responses made. [5] Use online panels because quotas and screening can help to target the proper respondents in a demographically balanced manner. [11]	To not have a self-selected group, non-probability sampling should meet the condition of sufficient response rate. [1] These procedures should be considered for achieving the desired level of randomness and representativeness of non-probability samples.      • Random selection of email addresses from newsgroup      • Use of stratified random samples of proprietary bulletin board users      • Employment of a sampling frame from list of users who have free access to internet      • Use of a stratified sample of individuals whose email-addresses are obtained from Usenet newsgroup.           [5] Direct effort at decreasing the occurrence of sampling measurement and non-response errors. [5] Bias must be avoided, both in the selection of the population being studied and in the responses made. [5] Used web surveys when wide geographic coverage is sought. [11] Have a database with valid e-mail addresses and permission by potential respondents to send surveys. [1] Use online panels because quotas and screening can help to target the proper respondents in a demographically balanced manner. [1]	To not have a self-selected group, non-probability sampling should meet the condition of sufficient response rate. [1] These procedures should be considered for achieving the desired level of randomness and representativeness of non-probability samples.      • Random selection of email addresses from newsgroup      • Use of stratified random samples of proprietary bulletin board users      • Employment of a sampling frame from list of users who have free access to internet      • Use of a stratified sample of individuals whose email-addresses are obtained from Usenet newsgroup.           [5] Direct effort at decreasing the occurrence of sampling measurement and non-response errors. [5] Bias must be avoided, both in the selection of the population being studied and in the responses made. [5] Used web surveys when wide geographic coverage is sought. [11] Have a database with valid e-mail addresses and permission by potential respondents to send surveys. [1] Use online panels because quotas and screening can help to target the proper respondents in a demographically balanced manner. [1]	To not have a self-selected group, non-probability sampling should meet the condition of sufficient response rate. [1] Direct effort at decreasing the occurrence of sampling measurement and non-response errors. [5] Bias must be avoided, both in the selection of the population being studied and in the responses made. [5] Used web surveys when wide geographic coverage is sought. [11] Use online panels because quotas and screening can help to target the proper respondents in a demographically balanced manner. [1]
	Training	Consider the idea to make a short period of training in order to make patients capable of using the system. [1]
	Testing and pretesting	Perform tests to verify the quality of the questionnaire: • Pre testing-to ensure a clear interpretation of individual questions • Pilot testing-to review the relevance, flow, arrangement and wording of the questionnaire • Clinical sensibility testing-to ensure the adherence of the questionnaire to the survey objective.     [11] Development plan and acceptance testing must test the suitability of the application. [9] Do not test every aspect of the application, simplify the testing requirement using design based on principles have been tried in similar context in the past. [11] The competence test must verify technical and executive capabilities, imperfections and answer problems of the questionnaire. [11] Test the questionnaire using monitors with different resolutions in order to ensure the comprehensibility. [6] Sometimes is better to repeat questions slightly reworded in order to assess consistency of response. [6] Questionnaire pre-test is useful if it is done with multiple browsers and screen settings in order to ensure their applicability and accessibility. [12] Pre-test is useful to reduce the problem of unclear answering instructions; it is recommended the use of opt-in popup windows that can be accessed if a question is not understood. [1] Set the tab order on the pages to ensure the that text is readable in a logical way. [1] Run the pre-test on various members of the target group or on an experts group. [13]	Perform tests to verify the quality of the questionnaire: • Pre testing-to ensure a clear interpretation of individual questions • Pilot testing-to review the relevance, flow, arrangement and wording of the questionnaire • Clinical sensibility testing-to ensure the adherence of the questionnaire to the survey objective.     [14] Development plan and acceptance testing must test the suitability of the application. [9] Do not test every aspect of the application, simplify the testing requirement using design based on principles have been tried in similar context in the past. [11] The competence test must verify technical and executive capabilities, imperfections and answer problems of the questionnaire. [11] Ensure that the arrangement and formation of sent file do not change after receiving or responding the email questionnaire. [6] Test the questionnaire using several Web explorers and monitors with different resolutions in order to ensure the comprehensibility. [6] Sometimes is better to repeat questions slightly reworded in order to assess consistency of response. [6] Questionnaire pre-test is useful if it is done with multiple browsers and screen settings in order to ensure their applicability and accessibility. [12] Pre-test is useful to reduce the problem of unclear answering instructions; it is recommended the use of opt-in popup windows that can be accessed if a question is not understood. [1] Set the tab order on the pages to ensure the that text is readable in a logical way. [1] Run the pre-test on various members of the target group or on an experts group. [13] For Web and e-mail questionnaire, virtual pretesting and testing is useful to ensure quick and effective control of the questionnaire. [14]	Perform tests to verify the quality of the questionnaire: • Pre testing-to ensure a clear interpretation of individual questions • Pilot testing-to review the relevance, flow, arrangement and wording of the questionnaire • Clinical sensibility testing-to ensure the adherence of the questionnaire to the survey objective.     [14] Development plan and acceptance testing must test the suitability of the application. [9] Do not test every aspect of the application, simplify the testing requirement using design based on principles have been tried in similar context in the past. [11] The competence test must verify technical and executive capabilities, imperfections and answer problems of the questionnaire. [11] Test the questionnaire using several Web explorers and monitors with different resolutions in order to ensure the comprehensibility. [6] Sometimes is better to repeat questions slightly reworded in order to assess consistency of response. [6] Questionnaire pre-test is useful if it is done with multiple browsers and screen settings in order to ensure their applicability and accessibility. [12] Pre-test is useful to reduce the problem of unclear answering instructions; it is recommended the use of opt-in popup windows that can be accessed if a question is not understood. [1] Set the tab order on the pages to ensure the that text is readable in a logical way. [1] Run the pre-test on various members of the target group or on an experts group. [13] For Web and e-mail questionnaire, virtual pretesting and testing is useful to ensure quick and effective control of the questionnaire. [14]	Perform tests to verify the quality of the questionnaire: • Pre testing-to ensure a clear interpretation of individual questions • Pilot testing-to review the relevance, flow, arrangement and wording of the questionnaire • Clinical sensibility testing-to ensure the adherence of the questionnaire to the survey objective.     [14] Development plan and acceptance testing must test the suitability of the application. [9] Do not test every aspect of the application, simplify the testing requirement using design based on principles have been tried in similar context in the past. [11] The competence test must verify technical and executive capabilities, imperfections and answer problems of the questionnaire. [11] Test the questionnaire using several Web explorers and monitors with different resolutions in order to ensure the comprehensibility. [6] Sometimes is better to repeat questions slightly reworded in order to assess consistency of response. [6] Questionnaire pre-test is useful if it is done with multiple browsers and screen settings in order to ensure their applicability and accessibility. [12] Pre-test is useful to reduce the problem of unclear answering instructions; it is recommended the use of opt-in popup windows that can be accessed if a question is not understood. [1] Set the tab order on the pages to ensure the that text is readable in a logical way. [1] Run the pre-test on various members of the target group or on an experts group. [13] For Web and e-mail questionnaire, virtual pretesting and testing is useful to ensure quick and effective control of the questionnaire. [14]
	Reliability test	Run a test-retest reliability whether the same question posed to the same individual yields consistent results at different times. [14] Ensure the interrater reliability if you expect different respondents provide similar responses. [9] Ensure the internal consistency, verifying that different items tapping into the same construct are correlated. [9] The reliability assessment must depend on the objective of the survey and the type of data collected. [9]	Run a test-retest reliability whether the same question posed to the same individual yields consistent results at different times. [9] Ensure the interrater reliability if you expect different respondents provide similar responses. [9] Ensure the internal consistency, verifying that different items tapping into the same construct are correlated. [9] The reliability assessment must depend on the objective of the survey and the type of data collected. [9]	Run a test-retest reliability whether the same question posed to the same individual yields consistent results at different times. [9] Ensure the interrater reliability if you expect different respondents provide similar responses. [9] Ensure the internal consistency, verifying that different items tapping into the same construct are correlated. [9] The reliability assessment must depend on the objective of the survey and the type of data collected. [9]	Run a test-retest reliability whether the same question posed to the same individual yields consistent results at different times. [9] Ensure the interrater reliability if you expect different respondents provide similar responses. [9] Ensure the internal consistency, verifying that different items tapping into the same construct are correlated. [9] The reliability assessment must depend on the objective of the survey and the type of data collected. [9]
	Validity test	Ensure face validity, testing whether the questionnaire measures what it intends to measure during clinical sensibility testing. [9] Ensure content validity, verifying if questionnaire content accurately assess all fundamental aspects of the topic. [9] Ensure construct validity if it is not possible to identify specific criteria that adequately define the construct being measured. [9] Define criterion validity, comparing questionnaire responses to a “gold standard”. [9] Engage investigators in one or more assessments of instrument validity, depending on current and anticipated uses of the questionnaire. [9]	Ensure face validity, testing whether the questionnaire measures what it intends to measure during clinical sensibility testing. [9] Ensure content validity, verifying if questionnaire content accurately assess all fundamental aspects of the topic. [9] Ensure construct validity if it is not possible to identify specific criteria that adequately define the construct being measured. [9] Define criterion validity, comparing questionnaire responses to a “gold standard”. [9] Engage investigators in one or more assessments of instrument validity, depending on current and anticipated uses of the questionnaire. [9]	Ensure face validity, testing whether the questionnaire measures what it intends to measure during clinical sensibility testing. [9] Ensure content validity, verifying if questionnaire content accurately assess all fundamental aspects of the topic. [9] Ensure construct validity if it is not possible to identify specific criteria that adequately define the construct being measured. [9] Define criterion validity, comparing questionnaire responses to a “gold standard”. [9] Engage investigators in one or more assessments of instrument validity, depending on current and anticipated uses of the questionnaire. [9]	Ensure face validity, testing whether the questionnaire measures what it intends to measure during clinical sensibility testing. [9] Ensure content validity, verifying if questionnaire content accurately assess all fundamental aspects of the topic. [9] Ensure construct validity if it is not possible to identify specific criteria that adequately define the construct being measured. [9] Define criterion validity, comparing questionnaire responses to a “gold standard”. [9] Engage investigators in one or more assessments of instrument validity, depending on current and anticipated uses of the questionnaire. [9]
QUESTIONNAIRE DESIGN	Profile the target audience	Tailor a questionnaire to the interests and style of the target audience. [9] The survey topic must be relevant to the target group. [5] Design the questionnaire in order to give the user the impression of participating in an interesting conversation. [5] Focus on in-the-moment data, because increases interest in the survey. [14] Adapt the survey protocols according legal and ethical considerations of the specific country and culture.	Tailor a questionnaire to the interests and style of the target audience. [15] The survey topic must be relevant to the target group. [5] Design the questionnaire in order to give the user the impression of participating in an interesting conversation. [5] Focus on in-the-moment data, because increases interest in the survey. [14] Adapt the survey protocols according legal and ethical considerations of the specific country and culture.	Tailor a questionnaire to the interests and style of the target audience. [15] The survey topic must be relevant to the target group. [5] Design the questionnaire in order to give the user the impression of participating in an interesting conversation. [5] Focus on in-the-moment data, because increases interest in the survey. [14] Adapt the survey protocols according legal and ethical considerations of the specific country and culture.	Tailor a questionnaire to the interests and style of the target audience. [15] The survey topic must be relevant to the target group. [5] Design the questionnaire in order to give the user the impression of participating in an interesting conversation. [5] Focus on in-the-moment data, because increases interest in the survey. [14] Adapt the survey protocols according legal and ethical considerations of the specific country and culture.
	Quality of data	Consider to collaborate with a biostatistician to ensure that data required for analyses are obtained in a usable format. [15] Consider that the collation of the data can be problematic, because consistent structure within responses can only be suggested, not enforced. [9] It is possible increase response rate and accuracy of responses by paying attention to access problems, the motivation and cognition of respondents. [5] Consider these sources’ effects: no interviewer, respondent control, visual processing of information. [5] Past research can be useful in order to develop an implementation strategy to improving respondent to self-administered questionnaires. [16] Analyze the phenomenon of non-response and it is possible causes: technological considerations, questionnaire design decisions, respondent computer skills, as well as implementation decisions. [16] In data collection do not consider default values, namely common or sensible values that are displayed before the user enters a value, and which are taken as data when the user does not make a specific choice. Responses should always result from an action by the user. [16] Improve the response rate creating a short and relevant survey, based on the interest of the target population. [11] Consider that the decision to participate at the questionnaire is influenced also by the flexibility of response time. [1] Ensure that the experience is comparable across different regions, by creating a survey protocol applicable in different context. [15]	Consider to collaborate with a biostatistician to ensure that data required for analyses are obtained in a usable format. [10] Consider that the collation of the data can be problematic, because consistent structure within responses can only be suggested, not enforced. [9] It is possible increase response rate and accuracy of responses by paying attention to access problems, the motivation and cognition of respondents. [5] Use properly the subject line of email messages in order to inform potential respondents of the study. [5] Consider these sources’ effects: no interviewer, respondent control, visual processing of information. [5] Past research can be useful in order to develop an implementation strategy to improving respondent to self-administered questionnaires. [16] Analyze the phenomenon of non-response and it is possible causes: technological considerations, questionnaire design decisions, respondent computer skills, as well as implementation decisions. [16] In data collection do not consider default values, namely common or sensible values that are displayed before the user enters a value, and which are taken as data when the user does not make a specific choice. Responses should always result from an action by the user. [16] Improve the response rate creating a short and relevant survey, based on the interest of the target population. [11] Consider that the decision to participate at the questionnaire is influenced also by the flexibility of response time. [1] Ensure that the experience is comparable across different regions, by creating a survey protocol applicable in different context. [15]	Consider to collaborate with a biostatistician to ensure that data required for analyses are obtained in a usable format. [10] Consider that the collation of the data can be problematic, because consistent structure within responses can only be suggested, not enforced. [9] It is possible increase response rate and accuracy of responses by paying attention to access problems, the motivation and cognition of respondents. [5] Use properly the subject line of email messages in order to inform potential respondents of the study. [5] Consider these sources’ effects: no interviewer, respondent control, visual processing of information. [5] Past research can be useful in order to develop an implementation strategy to improving respondent to self-administered questionnaires. [16] Analyze the phenomenon of non-response and it is possible causes: technological considerations, questionnaire design decisions, respondent computer skills, as well as implementation decisions. [16] In data collection do not consider default values, namely common or sensible values that are displayed before the user enters a value, and which are taken as data when the user does not make a specific choice. Responses should always result from an action by the user. [16] Improve the response rate creating a short and relevant survey, based on the interest of the target population. [11] Consider that the decision to participate at the questionnaire is influenced also by the flexibility of response time. [1] Ensure that the experience is comparable across different regions, by creating a survey protocol applicable in different context. [15]	Consider to collaborate with a biostatistician to ensure that data required for analyses are obtained in a usable format. [10] Consider that the collation of the data can be problematic, because consistent structure within responses can only be suggested, not enforced. [9] It is possible increase response rate and accuracy of responses by paying attention to access problems, the motivation and cognition of respondents. [5] Consider these sources’ effects: no interviewer, respondent control, visual processing of information. [5] Past research can be useful in order to develop an implementation strategy to improving respondent to self-administered questionnaires. [16] Analyze the phenomenon of non-response and it is possible causes: technological considerations, questionnaire design decisions, respondent computer skills, as well as implementation decisions. [16] In data collection do not consider default values, namely common or sensible values that are displayed before the user enters a value, and which are taken as data when the user does not make a specific choice. Responses should always result from an action by the user. [16] Improve the response rate creating a short and relevant survey, based on the interest of the target population. [11] Consider that the decision to participate at the questionnaire is influenced also by the flexibility of response time. [1] Ensure that the experience is comparable across different regions, by creating a survey protocol applicable in different context. [15] Ensure that online data is comparable with mobile data, despite the different mode of data collection. [10]
	Welcome page	Signatures of departmental stationery should be present. [10] Affirm that the recipient’s participation is imperative to the success of the survey. [9] Make sure that welcome page and first questions are relevant, fast, and easy. [9] Introduce the questionnaire with a welcome screen to motivate users, to emphasize the ease of responding and to teach the respondent how to proceed. [16] Include a short and understandable introduction to explain the topic of the survey. [12] Try to persuade participants to agree to be surveyed and to share personal data. [12] Explain clearly the aim of the survey. [1] Use the questionnaire’s introduction to capture the users’ interest. [14]	Signatures of departmental stationery should be present. [14] Affirm that the recipient’s participation is imperative to the success of the survey. [9] Make sure that welcome page and first questions are relevant, fast, and easy. [9] Introduce the questionnaire with a welcome screen to motivate users, to emphasize the ease of responding and to teach the respondent how to proceed. [16] Include a short and understandable introduction to explain the topic of the survey. [12] Try to persuade participants to agree to be surveyed and to share personal data. [12] Explain clearly the aim of the survey. [1] Use the questionnaire’s introduction to capture the users’ interest. [14]	Signatures of departmental stationery should be present. [14] Affirm that the recipient’s participation is imperative to the success of the survey. [9] Make sure that welcome page and first questions are relevant, fast, and easy. [9] Introduce the questionnaire with a welcome screen to motivate users, to emphasize the ease of responding and to teach the respondent how to proceed. [16] Include a short and understandable introduction to explain the topic of the survey. [12] Include a site map to help the users during the navigation. [12] Try to persuade participants to agree to be surveyed and to share personal data. [12] Explain clearly the aim of the survey. [1] Use the questionnaire’s introduction to capture the users’ interest. [14]	Signatures of departmental stationery should be present. [14] Affirm that the recipient’s participation is imperative to the success of the survey. [9] Make sure that welcome page and first questions are relevant, fast, and easy. [9] Introduce the questionnaire with a welcome screen to motivate users, to emphasize the ease of responding and to teach the respondent how to proceed. [16] Include a short and understandable introduction to explain the topic of the survey. [12] Include a site map to help the users during the navigation. [12] Try to persuade participants to agree to be surveyed and to share personal data. [12] Explain clearly the aim of the survey. [1] Use the questionnaire’s introduction to capture the users’ interest. [14]
	Open/ closed questions	Use open-ended questions if there are too many possible response options or when the response possibilities are unknown at the time of administering the questionnaire. [14] Use open-ended questions to not impose response categories onto the respondents. [12] Use open-ended questions with sparingly, because of the complexity of the analysis. [12] Use closed-ended questions when the goal is to obtain data that is ranked or rated and when the ratings’ order is know before. [12] Use closed-ended questions if statistical data is required and where is better to count the number of choices rather than analyze free text. [12] Closed-ended questions should be completeness, exclusivity and clarity. [12] In closed question, answer’s categories must be complete and should not overlap. [2]	Do not be reluctant to incorporate open ended items in the e-mail questionnaire. [14] Use open-ended questions if there are too many possible response options or when the response possibilities are unknown at the time of administering the questionnaire. [5] Use open-ended questions to not impose response categories onto the respondents. [12] Use open-ended questions with sparingly, because of the complexity of the analysis. [12] Use closed-ended questions when the goal is to obtain data that is ranked or rated and when the ratings’ order is know before. [12] Use closed-ended questions if statistical data is required and where is better to count the number of choices rather than analyze free text. [12] Closed-ended questions should be completeness, exclusivity and clarity. [12] In closed question, answer’s categories must be complete and should not overlap. [2]	Use open-ended questions if there are too many possible response options or when the response possibilities are unknown at the time of administering the questionnaire. [14] Use open-ended questions to not impose response categories onto the respondents. [12] Use open-ended questions with sparingly, because of the complexity of the analysis. [12] Use closed-ended questions when the goal is to obtain data that is ranked or rated and when the ratings’ order is know before. [12] Use closed-ended questions if statistical data is required and where is better to count the number of choices rather than analyze free text. [12] Closed-ended questions should be completeness, exclusivity and clarity. [12] In closed question, answer’s categories must be complete and should not overlap. [2]	Use open-ended questions if there are too many possible response options or when the response possibilities are unknown at the time of administering the questionnaire. [14] Use open-ended questions to not impose response categories onto the respondents. [12] Use open-ended questions with sparingly, because of the complexity of the analysis. [12] Use closed-ended questions when the goal is to obtain data that is ranked or rated and when the ratings’ order is know before. [12] Use closed-ended questions if statistical data is required and where is better to count the number of choices rather than analyze free text. [12] Closed-ended questions should be completeness, exclusivity and clarity. [12] In closed question, answer’s categories must be complete and should not overlap. [2] Prefer closed questions for app surveys. [14] Tailor the question types to the specific design constraints and strengths of the mobile devices. [15]
	Rank order questions	Rank order question can be used to require the user to rank items in a list according to some criteria. [10]	Rank order question can be used to require the user to rank items in a list according to some criteria. [12]	Rank order question can be used to require the user to rank items in a list according to some criteria. [12]	Rank order question can be used to require the user to rank items in a list according to some criteria. [12]
	Categorical or nominal questions	Categorical or nominal question can be used to require the user to chose one or more from a selection of categories listed as the response options. [12] Categories listed must be all inclusive and exhaustive. [12] Use this type of questions to obtain sensitive information. [12]	Categorical or nominal question can be used to require the user to chose one or more from a selection of categories listed as the response options. [12] Categories listed must be all inclusive and exhaustive. [12] Use this type of questions to obtain sensitive information. [12]	Categorical or nominal question can be used to require the user to chose one or more from a selection of categories listed as the response options. [12] Categories listed must be all inclusive and exhaustive. [12] Use this type of questions to obtain sensitive information. [12]	Categorical or nominal question can be used to require the user to chose one or more from a selection of categories listed as the response options. [12] Categories listed must be all inclusive and exhaustive. [12] Use this type of questions to obtain sensitive information. [12]
	Magnitude estimate questions	Magnitude estimate questions can be used to require comparative judgments. [12]	Magnitude estimate questions can be used to require comparative judgments. [12]	Magnitude estimate questions can be used to require comparative judgments. [12]	Magnitude estimate questions can be used to require comparative judgments. [12]
	Ordinal questions	Ordinal questions can be used only when the topic is well-defined and the response options represent a gradation along a single dimension. [12]	Ordinal questions can be used only when the topic is well-defined and the response options represent a gradation along a single dimension. [12]	Ordinal questions can be used only when the topic is well-defined and the response options represent a gradation along a single dimension. [12]	Ordinal questions can be used only when the topic is well-defined and the response options represent a gradation along a single dimension. [12]
	Likert scale questions	Likert scale questions can be used to require users to indicate their level of agreement with a particular statement. [12] Provide brief instruction per question to explain how answers should be provided. [12] Consider that the use of intermediate values of response can influence the choice of the user: patients are inclined to choose more neutral values.	Likert scale questions can be used to require users to indicate their level of agreement with a particular statement. [12] Provide brief instruction per question to explain how answers should be provided. [12] Consider that the use of intermediate values of response can influence the choice of the user: patients are inclined to choose more neutral values.	Likert scale questions can be used to require users to indicate their level of agreement with a particular statement. [12] Provide brief instruction per question to explain how answers should be provided. [12] Consider that the use of intermediate values of response can influence the choice of the user: patients are inclined to choose more neutral values.	Likert scale questions can be used to require users to indicate their level of agreement with a particular statement. [12] Provide brief instruction per question to explain how answers should be provided. [12] Consider that the use of intermediate values of response can influence the choice of the user: patients are inclined to choose more neutral values.
	Indeterminate and other response options	Include indeterminate or other response options, to avoid “floor and ceiling” effects. [12] Indeterminate response options can be used when binary responses are sought or when respondent knowledge is being probed. [9] Remove questions that demonstrate floor or ceiling effects, or use another response format to increase the range of responses. [9] Use “other” response options to enhance response rates in self administered questionnaires, or use them during questionnaire testing, in order to identify new issues or to elaborate on closed response formats. [9] Include a “do not know” and a “no opinion” response choice in knowledge questions. [9]	Include indeterminate or other response options, to avoid “floor and ceiling” effects. [12] Indeterminate response options can be used when binary responses are sought or when respondent knowledge is being probed. [9] Remove questions that demonstrate floor or ceiling effects, or use another response format to increase the range of responses. [9] Use “other” response options to enhance response rates in self administered questionnaires, or use them during questionnaire testing, in order to identify new issues or to elaborate on closed response formats. [9] Include a “do not know” and a “no opinion” response choice in knowledge questions. [9]	Include indeterminate or other response options, to avoid “floor and ceiling” effects. [12] Indeterminate response options can be used when binary responses are sought or when respondent knowledge is being probed. [9] Remove questions that demonstrate floor or ceiling effects, or use another response format to increase the range of responses. [9] Use “other” response options to enhance response rates in self administered questionnaires, or use them during questionnaire testing, in order to identify new issues or to elaborate on closed response formats. [9] Include a “do not know” and a “no opinion” response choice in knowledge questions. [9]	Include indeterminate or other response options, to avoid “floor and ceiling” effects. [12] Indeterminate response options can be used when binary responses are sought or when respondent knowledge is being probed. [9] Remove questions that demonstrate floor or ceiling effects, or use another response format to increase the range of responses. [9] Use “other” response options to enhance response rates in self administered questionnaires, or use them during questionnaire testing, in order to identify new issues or to elaborate on closed response formats. [9] Include a “do not know” and a “no opinion” response choice in knowledge questions. [9]
	Open/ closed responses	Use succinct and unbiased response formats, either “open” or “closed”. [12]	Use succinct and unbiased response formats, either “open” or “closed”. [9]	Use succinct and unbiased response formats, either “open” or “closed”. [9]	Use succinct and unbiased response formats, either “open” or “closed”. [9]
QUESTIONNAIRE LAYOUT	Questionnaire length	Pay attention to the length of the questionnaire: in general, questions are addressed with 25 or fewer items and at least 5 items in each domain. [9] The length of a questionnaire influences the response rate, because the questionnaire can take up the space of several computer screens. [9] When create a voluntary survey, be careful to keep the questionnaire short. [5] Keep just a few questions in each page. [16] Do not exceed the number of 60 questions in the entire questionnaire. [6] Do not exceed the number of 15-20 questions in the entire questionnaire. Use longer questionnaire only if the users are adequately prepared via a pre notification letter and it is sure that they are interested in the topic and approve of the study's aims. [12] Include only the most essential and relevant questions for the survey. [14] Be careful to the length of the questionnaire, including a small number of short, well focused, understandable questions, avoiding to require excessive concentration. [14] Specific the number of questions included in the questionnaire, in order to reduce the likelihood to abandonment. [17] Keep survey length short, in order to avoid that users speed through the survey to completion. [18]	Pay attention to the length of the questionnaire: in general, questions are addressed with 25 or fewer items and at least 5 items in each domain. [19] The length of a questionnaire influences the response rate, because the questionnaire can take up the space of several computer screens. [9] When create a voluntary survey, be careful to keep the questionnaire short. [5] Keep just a few questions in each page. [16] Do not exceed the number of 60 questions in the entire questionnaire. [6] Do not exceed the number of 15-20 questions in the entire questionnaire. Use longer questionnaire only if the users are adequately prepared via a pre notification letter and it is sure that they are interested in the topic and approve of the study's aims. [12] Include only the most essential and relevant questions for the survey. [14] Be careful to the length of the questionnaire, including a small number of short, well focused, understandable questions, avoiding to require excessive concentration. [14] Specific the number of questions included in the questionnaire, in order to reduce the likelihood to abandonment. [17] Keep survey length short, in order to avoid that users speed through the survey to completion. [18]	Pay attention to the length of the questionnaire: in general, questions are addressed with 25 or fewer items and at least 5 items in each domain. [19] The length of a questionnaire influences the response rate, because the questionnaire can take up the space of several computer screens. [9] The length of a questionnaire must change according to the type of questionnaire: an email questionnaire can be excessively long when placed on a Web site. [5] When create a voluntary survey, be careful to keep the questionnaire short. [5] Keep just a few questions in each page. [16] Do not exceed the number of 60 questions in the entire questionnaire. [6] Do not exceed the number of 15-20 questions in the entire questionnaire. Use longer questionnaire only if the users are adequately prepared via a pre notification letter and it is sure that they are interested in the topic and approve of the study's aims. [12] Include only the most essential and relevant questions for the survey. [14] Be careful to the length of the questionnaire, including a small number of short, well focused, understandable questions, avoiding to require excessive concentration. [14] Specific the number of questions included in the questionnaire, in order to reduce the likelihood to abandonment. [17] Keep survey length short, in order to avoid that users speed through the survey to completion. [18]	Pay attention to the length of the questionnaire: in general, questions are addressed with 25 or fewer items and at least 5 items in each domain. [19] The length of a questionnaire influences the response rate, because the questionnaire can take up the space of several device screens. [9] When create a voluntary survey, be careful to keep the questionnaire short. [5] Keep just a few questions in each page. [16] Do not exceed the number of 60 questions in the entire questionnaire. [6] Do not exceed the number of 15-20 questions in the entire questionnaire. Use longer questionnaire only if the users are adequately prepared via a pre notification letter and it is sure that they are interested in the topic and approve of the study's aims. [12] Include only the most essential and relevant questions for the survey. [14] Be careful to the length of the questionnaire, including a small number of short, well focused, understandable questions, avoiding to require excessive concentration. [14] Specific the number of questions included in the questionnaire, in order to reduce the likelihood to abandonment. [17] Keep survey length short, especially in mobile research, in order to avoid that users speed through the survey to completion. [18]
	Questionnaire structure and questions’ order	At first, include simple questions or demographic questions. [19] Include sensitive questions at the end of the questionnaire. [9] Make sure that the initial questions is routine and easy-to-answer questions in order to arouse user’s interest. [9] At the first question include an item that is likely to be interesting, easy to answer, and fully visible on the first screen of the questionnaire. [12] Number consecutively and organize questions according on content and structure. [14] Organize the questionnaire in order to facilitate questionnaire flow. [9, 16] Ask one question at time. [9] Use an item-in-a-series format to place items with the same response categories. [16] Include useful graphical languages to facilitate user’s navigation through the desired response path. [16] Present and organize the questionnaire so that it is attractive and easy to complete, without including too much information for page and align elements horizontally or vertically in order to facilitate the reading. [16] Include delicate, tricky and the most important questions at 1/3 of the questionnaire, when the user has already start to complete it, but he’s not yet bored. [12] Include open-ended questions at the 2/3 of the questionnaire, in order to maintain the users’ interest. [12] If the topic is the same, include open-ended questions before closed-ended questions, to avoid influencing respondents with the fixed option choices. [12] Do not separate a question from its response set. [12] Avoid to require that a user provide an answer to one question before moving on to the next question. [12] In order to reduce survey bias, directs users’ navigation, requiring them to answer questions in the order intended by the study designer. [12] The initial question must be fully visible on the first screen of the questionnaire, interest-getting, easily comprehended and answered by all respondents. Do not use drop-down box or require scrolling in order to see the entire first question. [12]	At first, include simple questions or demographic questions. [20] Include sensitive questions at the end of the questionnaire. [9] Make sure that the initial questions is routine and easy-to-answer questions in order to arouse user’s interest. [9] At the first question include an item that is likely to be interesting, easy to answer, and fully visible on the first screen of the questionnaire. [12] Number consecutively and organize questions according on content and structure. [14] Organize the questionnaire in order to facilitate questionnaire flow. [9, 16] Ask one question at time. [9] Use an item-in-a-series format to place items with the same response categories. [16] Include useful graphical languages to facilitate user’s navigation through the desired response path. [16] Present and organize the questionnaire so that it is attractive and easy to complete, without including too much information for page and align elements horizontally or vertically in order to facilitate the reading. [16] Include delicate, tricky and the most important questions at 1/3 of the questionnaire, when the user has already start to complete it, but he’s not yet bored. [12] Include open-ended questions at the 2/3 of the questionnaire, in order to maintain the users’ interest. [12] If the topic is the same, include open-ended questions before closed-ended questions, to avoid influencing respondents with the fixed option choices. [12] Do not separate a question from its response set. [12] Avoid to require that a user provide an answer to one question before moving on to the next question. [12] In order to reduce survey bias, directs users’ navigation, requiring them to answer questions in the order intended by the study designer. [12] The initial question must be fully visible on the first screen of the questionnaire, interest-getting, easily comprehended and answered by all respondents. Do not use drop-down box or require scrolling in order to see the entire first question. [12]	At first, include simple questions or demographic questions. [20] Include sensitive questions at the end of the questionnaire. [9] Make sure that the initial questions is routine and easy-to-answer questions in order to arouse user’s interest. [9] At the first question include an item that is likely to be interesting, easy to answer, and fully visible on the first screen of the questionnaire. [12] Number consecutively and organize questions according on content and structure. [14] Organize the questionnaire in order to facilitate questionnaire flow. [9, 16] Ask one question at time. [9] Use an item-in-a-series format to place items with the same response categories. [16] Include useful graphical languages to facilitate user’s navigation through the desired response path. [16] Present and organize the questionnaire so that it is attractive and easy to complete, without including too much information for page and align elements horizontally or vertically in order to facilitate the reading. [16] Include delicate, tricky and the most important questions at 1/3 of the questionnaire, when the user has already start to complete it, but he’s not yet bored. [12] Include open-ended questions at the 2/3 of the questionnaire, in order to maintain the users’ interest. [12] If the topic is the same, include open-ended questions before closed-ended questions, to avoid influencing respondents with the fixed option choices. [12] Do not separate a question from its response set. [12] Avoid to require that a user provide an answer to one question before moving on to the next question. [12] In order to reduce survey bias, directs users’ navigation, requiring them to answer questions in the order intended by the study designer. [12] The initial question must be fully visible on the first screen of the questionnaire, interest-getting, easily comprehended and answered by all respondents. Do not use drop-down box or require scrolling in order to see the entire first question. [12]	At first, include simple questions or demographic questions. [20] Include sensitive questions at the end of the questionnaire. [9] Make sure that the initial questions is routine and easy-to-answer questions in order to arouse user’s interest. [9] At the first question include an item that is likely to be interesting, easy to answer, and fully visible on the first screen of the questionnaire. [12] Number consecutively and organize questions according on content and structure. [14] Organize the questionnaire in order to facilitate questionnaire flow. [9, 16] Ask one question at time. [9] Use an item-in-a-series format to place items with the same response categories. [16] Include useful graphical languages to facilitate user’s navigation through the desired response path. [16] Present and organize the questionnaire so that it is attractive and easy to complete, without including too much information for page and align elements horizontally or vertically in order to facilitate the reading. [16] Include delicate, tricky and the most important questions at 1/3 of the questionnaire, when the user has already start to complete it, but he’s not yet bored. [12] Include open-ended questions at the 2/3 of the questionnaire, in order to maintain the users’ interest. [12] If the topic is the same, include open-ended questions before closed-ended questions, to avoid influencing respondents with the fixed option choices. [12] Do not separate a question from its response set. [12] Avoid to require that a user provide an answer to one question before moving on to the next question. [12] In order to reduce survey bias, directs users’ navigation, requiring them to answer questions in the order intended by the study designer. [12] The initial question must be fully visible on the first screen of the questionnaire, interest-getting, easily comprehended and answered by all respondents. Do not use drop-down box or require scrolling in order to see the entire first question. [12]
	Layout	Pay attention to spatial arrangement, color, brightness and consistency, when you create the visual presentation of a questionnaire. [20] It is better to create a plain questionnaire than a fancy version of the same questionnaire, because a plain version increases response rate, the completeness and reduces completion time. [9] Limit the use of matrices where necessary. [5] In order to ensure an easy reading use a consistent figure/ground format and limit the use of reverse print to section headings and/or question numbers. [16] Try to respect the consistency of the questionnaire also in the direction in which the scales are displayed. [16] It is better to use shorter lines to avoid words’ skip. [16] Highlight, but sparingly, words and phrases that indicate item’s change. [16] Make sure that questionnaire’s visual appearance is consistent to the designer’s measurement intentions and to the aim of the survey. [16] Use simple construction techniques, in order to not require multiple steps to answer items. [16] Design the questionnaire using a conventional formula similar to those normally used on paper self administered questionnaires. [16] Use the most challenging system, when administering the questionnaire through a PDA used as personal organizer. [16] Write sentences with no more than 20 words and with no more than 75 characters per line. Include paragraphs with no more than 5 sentences. [11] Do not divide the questionnaire in too many sections, in order to not confuse the users and make always clear survey’s focus. [12] Design simple and not overcrowded pages. Do not use pop-up windows, rollover text, cascading menus, and new browser windows; if pop-up windows are used, make sure that the default option is the most forgiving and if new browser windows are opened, make sure that a simple means to get back to the original is provided. [12] Choose a layout that don’t influence users’ opinions and answers. [12] Do not choose a columnar format with two-column design or multiple columns to present questionnaire’s text, in order to prevent that the user choose the wrong questions’ grid, and to avoid that the users forget to respond to subsequent columns before moving to the next page. [14] Design the questionnaire based on the question types supported (single choice, multi-choice, open ends). [18]	Pay attention to spatial arrangement, color, brightness and consistency, when you create the visual presentation of a questionnaire. [10] It is better to create a plain questionnaire than a fancy version of the same questionnaire, because a plain version increases response rate, the completeness and reduces completion time. [9] Limit the use of matrices where necessary. [5] In order to ensure an easy reading use a consistent figure/ground format and limit the use of reverse print to section headings and/or question numbers. [16] Try to respect the consistency of the questionnaire also in the direction in which the scales are displayed. [16] It is better to use shorter lines to avoid words’ skip. [16] Highlight, but sparingly, words and phrases that indicate item’s change. [16] Make sure that questionnaire’s visual appearance is consistent to the designer’s measurement intentions and to the aim of the survey. [16] Use simple construction techniques, in order to not require multiple steps to answer items. [16] Design the questionnaire using a conventional formula similar to those normally used on paper self administered questionnaires. [16] Use the most challenging system, when administering the questionnaire through a PDA used as personal organizer. [16] Write sentences with no more than 20 words and with no more than 75 characters per line. Include paragraphs with no more than 5 sentences. [11] Do not divide the questionnaire in too many sections, in order to not confuse the users and make always clear survey’s focus. [12] Design simple and not overcrowded pages. Do not use pop-up windows, rollover text, cascading menus, and new browser windows; if pop-up windows are used, make sure that the default option is the most forgiving and if new browser windows are opened, make sure that a simple means to get back to the original is provided. [12] Choose a layout that don’t influence users’ opinions and answers. [12] Do not choose a columnar format with two-column design or multiple columns to present questionnaire’s text, in order to prevent that the user choose the wrong questions’ grid, and to avoid that the users forget to respond to subsequent columns before moving to the next page. [14] Design the questionnaire based on the question types supported (single choice, multi-choice, open ends). [18]	Pay attention to spatial arrangement, color, brightness and consistency, when you create the visual presentation of a questionnaire. [10] It is better to create a plain questionnaire than a fancy version of the same questionnaire, because a plain version increases response rate, the completeness and reduces completion time. [9] Limit the use of matrices where necessary. [5] In order to ensure an easy reading use a consistent figure/ground format and limit the use of reverse print to section headings and/or question numbers. [16] Try to respect the consistency of the questionnaire also in the direction in which the scales are displayed. [16] It is better to use shorter lines to avoid words’ skip. [16] Highlight, but sparingly, words and phrases that indicate item’s change. [16] Make sure that questionnaire’s visual appearance is consistent to the designer’s measurement intentions and to the aim of the survey. [16] Use simple construction techniques, in order to not require multiple steps to answer items. [16] Design the questionnaire using a conventional formula similar to those normally used on paper self administered questionnaires. [16] Use the most challenging system, when administering the questionnaire through a PDA used as personal organizer. [16] Write sentences with no more than 20 words and with no more than 75 characters per line. Include paragraphs with no more than 5 sentences. [11] Do not divide the questionnaire in too many sections, in order to not confuse the users and make always clear survey’s focus. [12] Design simple and not overcrowded pages. Do not use pop-up windows, rollover text, cascading menus, and new browser windows; if pop-up windows are used, make sure that the default option is the most forgiving and if new browser windows are opened, make sure that a simple means to get back to the original is provided. [12] Choose a layout that don’t influence users’ opinions and answers. [12] Do not choose a columnar format with two-column design or multiple columns to present questionnaire’s text, in order to prevent that the user choose the wrong questions’ grid, and to avoid that the users forget to respond to subsequent columns before moving to the next page. [14] Design the questionnaire based on the question types supported (single choice, multi-choice, open ends). [18]	Pay attention to spatial arrangement, color, brightness and consistency, when you create the visual presentation of a questionnaire. [10] It is better to create a plain questionnaire than a fancy version of the same questionnaire, because a plain version increases response rate, the completeness and reduces completion time. [9] Limit the use of matrices where necessary. [5] In order to ensure an easy reading use a consistent figure/ground format and limit the use of reverse print to section headings and/or question numbers. [16] Try to respect the consistency of the questionnaire also in the direction in which the scales are displayed. [16] It is better to use shorter lines to avoid words’ skip. [16] Highlight, but sparingly, words and phrases that indicate item’s change. [16] Make sure that questionnaire’s visual appearance is consistent to the designer’s measurement intentions and to the aim of the survey. [16] Use simple construction techniques, in order to not require multiple steps to answer items. [16] Design the questionnaire using a conventional formula similar to those normally used on paper self administered questionnaires. [16] Use the most challenging system, when administering the questionnaire through a PDA used as personal organizer. [16] Write sentences with no more than 20 words and with no more than 75 characters per line. Include paragraphs with no more than 5 sentences. [11] Do not divide the questionnaire in too many sections, in order to not confuse the users and make always clear survey’s focus. [12] Design simple and not overcrowded pages. Do not use pop-up windows, rollover text, cascading menus, and new browser windows; if pop-up windows are used, make sure that the default option is the most forgiving and if new browser windows are opened, make sure that a simple means to get back to the original is provided. [12] Choose a layout that don’t influence users’ opinions and answers. [12] In mobile questionnaire, it is better to fit the question on the screen including the entire scale and all its items. If this is not possible, check that the respondent can effectively scroll the question or zoom in and out to gain an overview of all options. [14] Consider the number of points in the scale carefully: 5-point scales is convenient for a mobile phone screen (size 3,5”), since they fitted the screen easily with a readable font size. [17] Make selecting an icon or item for answering easy. On touch screen devices, use large enough icons and adequate spacing between items, so that the neighboring items or icons are not selected by accident. [17] Do not choose a columnar format with two-column design or multiple columns to present questionnaire’s text, in order to prevent that the user choose the wrong questions’ grid, and to avoid that the users forget to respond to subsequent columns before moving to the next page. [17] Design the questionnaire based on the question types supported (single choice, multi-choice, open ends). [18]
	Scrolling	Chose scroll, page by page, or mixed construction on the base of measurement and response considerations. [10] Do not include question structures that require scrolling or toggling between screens. [16] Do not use scroll bars in ePRO applications, since it is better to make all information simultaneously available on the screen. [16] Limit the need for scrolling, in particular design the welcome page into a single screen so it is not necessary to scroll. [11] Inform the users of the need to scroll. [12] Use jump buttons as alternative to scroll bars, to guide the users to the next screen. [12] Prefer the use of paging function like “page up” and “page down” keys as alternative to scrolling. [12]	Chose scroll, page by page, or mixed construction on the base of measurement and response considerations. [2] Do not include question structures that require scrolling or toggling between screens. [16] Do not use scroll bars in ePRO applications, since it is better to make all information simultaneously available on the screen. [16] Limit the need for scrolling, in particular design the welcome page into a single screen so it is not necessary to scroll. [11] Inform the users of the need to scroll. [12] Use jump buttons as alternative to scroll bars, to guide the users to the next screen. [12] Prefer the use of paging function like “page up” and “page down” keys as alternative to scrolling. [12] Design web questionnaires so they scroll from question to question without order mistakes. [2] Reduce the need of scrolling, and think to use the hyperlink to facilitate the change from one question to another one. [14]	Chose scroll, page by page, or mixed construction on the base of measurement and response considerations. [14] Do not include question structures that require scrolling or toggling between screens. [16] Do not use scroll bars in ePRO applications, since it is better to make all information simultaneously available on the screen. [16] Limit the need for scrolling, in particular design the welcome page into a single screen so it is not necessary to scroll. [11] Inform the users of the need to scroll. [12] Use jump buttons as alternative to scroll bars, to guide the users to the next screen. [12] Prefer the use of paging function like “page up” and “page down” keys as alternative to scrolling. [12] Design web questionnaires so they scroll from question to question without order mistakes. [2] Reduce the need of scrolling, and think to use the hyperlink to facilitate the change from one question to another one. [14]	Chose scroll, page by page, or mixed construction on the base of measurement and response considerations. [14] Do not include question structures that require scrolling or toggling between screens. [16] Limit the need for scrolling, in particular design the welcome page into a single screen so it is not necessary to scroll. [16] Inform the users of the need to scroll. [12] Use jump buttons as alternative to scroll bars, to guide the users to the next screen. [12] Prefer the use of paging function like “page up” and “page down” keys as alternative to scrolling. [12] Design web questionnaires so they scroll from question to question without order mistakes. [2] Reduce the need of scrolling, and think to use the hyperlink to facilitate the change from one question to another one. [2]
	Font size and style	Use a font style and size easy to read, like Arial 10–12 point. [14] Use bold type, shading and broad lines to help direct respondents’ attention. [9] Use a font size of 12 point. [9] Use readable and familiar fonts, presenting mixed case text or standard sentence formatting. [11] Use upper case or all capitals only for emphasis. [12] Test font colors and size with a screen magnifier before questionnaire distribution. [12]	Use a font style and size easy to read, like Arial 10–12 point. [12] Use bold type, shading and broad lines to help direct respondents’ attention. [9] Use a font size of 12 point. [9] Use readable and familiar fonts, presenting mixed case text or standard sentence formatting. [11] Use upper case or all capitals only for emphasis. [12] Test font colors and size with a screen magnifier before questionnaire distribution. [12]	Use a font style and size easy to read, like Arial 10–12 point. [12] Use bold type, shading and broad lines to help direct respondents’ attention. [9] Use a font size of 12 point. [9] Use readable and familiar fonts, presenting mixed case text or standard sentence formatting. [11] Use upper case or all capitals only for emphasis. [12] Test font colors and size with a screen magnifier before questionnaire distribution. [12]	Use a font style and size easy to read, like Arial 10–12 point. [12] Use bold type, shading and broad lines to help direct respondents’ attention. [9] Use a font size of 12 point. [9] Use readable and familiar fonts, presenting mixed case text or standard sentence formatting. [11] Use upper case or all capitals only for emphasis. [12] Test font colors and size with a screen magnifier before questionnaire distribution. [12] Ensure that is not necessary to zooming to read the text: it may be difficult due to the device used or due to context related issues. [12]
	Color	It is better to use dark print for questions and light print for answer choices. [17] Use a lightly shaded background colors on which to write all questions, and evidence all answer spaces in white in order to reduce item non-response. [16] Do not use red and green colors for necessary information, but only to enhance or clarify screen display. [16] Use consistent color coding throughout the questionnaire. [11] Use a neutral background color in order to make text very easy to read. [12] Use colors of high contrast when pairing colors or using two colors in close proximity. [12] Consider standard color associations among different cultures. [12] Limit the use of color in order to maintain figure/ground consistency and read-ability and consent an easy navigational flow. [12]	It is better to use dark print for questions and light print for answer choices. [14] Use a lightly shaded background colors on which to write all questions, and evidence all answer spaces in white in order to reduce item non-response. [16] Do not use red and green colors for necessary information, but only to enhance or clarify screen display. [16] Use consistent color coding throughout the questionnaire. [11] Use a neutral background color in order to make text very easy to read. [12] Use colors of high contrast when pairing colors or using two colors in close proximity. [12] Consider standard color associations among different cultures. [12] Limit the use of color in order to maintain figure/ground consistency and read-ability and consent an easy navigational flow. [12]	It is better to use dark print for questions and light print for answer choices. [14] Use a lightly shaded background colors on which to write all questions, and evidence all answer spaces in white in order to reduce item non-response. [16] Do not use red and green colors for necessary information, but only to enhance or clarify screen display. [16] Use consistent color coding throughout the questionnaire. [11] Use a neutral background color in order to make text very easy to read. [12] Use colors of high contrast when pairing colors or using two colors in close proximity. [12] Consider standard color associations among different cultures. [12] Limit the use of color in order to maintain figure/ground consistency and read-ability and consent an easy navigational flow. [12]	It is better to use dark print for questions and light print for answer choices. [14] Use a lightly shaded background colors on which to write all questions, and evidence all answer spaces in white in order to reduce item non-response. [16] Do not use red and green colors for necessary information, but only to enhance or clarify screen display. [16] Use consistent color coding throughout the questionnaire. [11] Use a neutral background color in order to make text very easy to read. [12] Use colors of high contrast when pairing colors or using two colors in close proximity. [12] Consider standard color associations among different cultures. [12] Limit the use of color in order to maintain figure/ground consistency and read-ability and consent an easy navigational flow. [12]
	Questions’ graphic	Dispose questions in the upper left quadrant. Information not needed by respondent must be placed into the lower left quadrant. [14] Evidence the beginning of each question in a consistent way. [16] Include blank space between the questions; less blank space should be placed between subcomponents of the same question. [16] Aligns vertically the question’s subcomponents in order to make easier the response task. [16] Check that there is no difference in the visual appearance of questions resulting from different screen configurations, operating systems, browsers, partial screen displays, and wrap-around text. [16] Make sure that questions’ format is distinguishable from instructions’ and answers’ format. [16] Separate clearly the question stem from the answer spaces. [13] Present questions in a conventional format similar to paper questionnaires’ format. [20] Layout questions as they are easy to read for the users, and evidence the most important keywords. [20] Evidence the references between question and corresponding answer. [14] Make clearly the difference between questions and answers with similarly format. [14]	Dispose questions in the upper left quadrant. Information not needed by respondent must be placed into the lower left quadrant. [14] Evidence the beginning of each question in a consistent way. [16] Include blank space between the questions; less blank space should be placed between subcomponents of the same question. [16] Aligns vertically the question’s subcomponents in order to make easier the response task. [16] Check that there is no difference in the visual appearance of questions resulting from different screen configurations, operating systems, browsers, partial screen displays, and wrap-around text. [16] Make sure that questions’ format is distinguishable from instructions’ and answers’ format. [16] Separate clearly the question stem from the answer spaces. [13] Present questions in a conventional format similar to paper questionnaires’ format. [20] Layout questions as they are easy to read for the users, and evidence the most important keywords. [20] Evidence the references between question and corresponding answer. [14] Make clearly the difference between questions and answers with similarly format. [14]	Dispose questions in the upper left quadrant. Information not needed by respondent must be placed into the lower left quadrant. [14] Evidence the beginning of each question in a consistent way. [16] Include blank space between the questions; less blank space should be placed between subcomponents of the same question. [16] Aligns vertically the question’s subcomponents in order to make easier the response task. [16] Check that there is no difference in the visual appearance of questions resulting from different screen configurations, operating systems, browsers, partial screen displays, and wrap-around text. [16] Make sure that questions’ format is distinguishable from instructions’ and answers’ format. [16] Separate clearly the question stem from the answer spaces. [13] Present questions in a conventional format similar to paper questionnaires’ format. [20] Layout questions as they are easy to read for the users, and evidence the most important keywords. [20] Evidence the references between question and corresponding answer. [14] Make clearly the difference between questions and answers with similarly format. [14]	Dispose questions in the upper left quadrant. Information not needed by respondent must be placed into the lower left quadrant. [14] Evidence the beginning of each question in a consistent way. [16] Include blank space between the questions; less blank space should be placed between subcomponents of the same question. [16] Aligns vertically the question’s subcomponents in order to make easier the response task. [16] Check that there is no difference in the visual appearance of questions resulting from different screen configurations, operating systems, browsers, partial screen displays, and wrap-around text. [16] Make sure that questions’ format is distinguishable from instructions’ and answers’ format. [16] Separate clearly the question stem from the answer spaces. [13] Present questions in a conventional format similar to paper questionnaires’ format. [20] Layout questions as they are easy to read for the users, and evidence the most important keywords. [20] Evidence the references between question and corresponding answer. [14] Make clearly the difference between questions and answers with similarly format. [14]
	Answers’ graphic	Receive the response options on separate lines. [14] Place answer categories vertically. [9] Place answer spaces consistently to the left or right of the category labels. [16] To facilitate the answer process, use numbers or simple answer boxes. [16] Ensure that space between answer choices is consistent with measurement intent. [16] Ensure that the area to be tapped is large enough to make easy the selection of a response option. [16] Make immediately visible the users’ answer to questions in order to evidence the effect of their actions. [11] Design answer items so are clearly related to the proper questions. [12]	Receive the response options on separate lines. [14] Place answer categories vertically. [9] Place answer spaces consistently to the left or right of the category labels. [16] To facilitate the answer process, use numbers or simple answer boxes. [16] Ensure that space between answer choices is consistent with measurement intent. [16] Ensure that the area to be tapped is large enough to make easy the selection of a response option. [16] Make immediately visible the users’ answer to questions in order to evidence the effect of their actions. [11] Design answer items so are clearly related to the proper questions. [12]	Receive the response options on separate lines. [14] Place answer categories vertically. [9] Place answer spaces consistently to the left or right of the category labels. [16] To facilitate the answer process, use numbers or simple answer boxes. [16] Ensure that space between answer choices is consistent with measurement intent. [16] Ensure that the area to be tapped is large enough to make easy the selection of a response option. [16] Make immediately visible the users’ answer to questions in order to evidence the effect of their actions. [11] Design answer items so are clearly related to the proper questions. [12]	Receive the response options on separate lines. [14] Place answer categories vertically. [9] Place answer spaces consistently to the left or right of the category labels. [16] To facilitate the answer process, use numbers or simple answer boxes. [16] Ensure that space between answer choices is consistent with measurement intent. [16] Ensure that the area to be tapped is large enough to make easy the selection of a response option. [16] Make immediately visible the users’ answer to questions in order to evidence the effect of their actions. [11] Design answer items so are clearly related to the proper questions. [12]
	Symbols and imagines	It is better to use large and bright symbols to identify the starting point on each page. [14] Use graphical languages to facilitate the logical flow of the questionnaire. [16] Consider the different meanings of symbols among different cultures. [16] Use the graphic only to increase the user’s motivation, download speed improvement and tiredness reduction. [11] Ensure that pictures and graphics not lead to misunderstanding. [6] Use hyper text, colors, interaction strategies and other Web communication capabilities to create more attraction. [6] Keep the number of graphics at minimum to avoid increasing download time and making difficult the accessibility of questionnaires across the sample. [6] Prefer small graphics that will download quickly: individual images should not exceed 5KB in size and single web-page should not exceed 20KB of graphics in total. [12] Include a text only version of the webpage, in addition that with graphics. [12] Use crisp and clear images to benefit users with visual disabilities. Remember to not blur pictures, grey out information or overlap menus. [12] Make sure that users can skip multimedia content without penalty. It is better to avoid multimedia and audio clips with graphics if users have to download the plug ins to complete the questionnaire. [12] Use logotypes in order to reduce item non-response and the tendency of users to choose the middle point of a rating scale. [12] The use of graphical symbols or words is useful to indicate user’s progress through questionnaire. [2] Avoid graphics and symbols that require significant increase in computer memory. [14]	It is better to use large and bright symbols to identify the starting point on each page. [14] Use graphical languages to facilitate the logical flow of the questionnaire. [16] Consider the different meanings of symbols among different cultures. [16] Use the graphic only to increase the user’s motivation, download speed improvement and tiredness reduction. [11] Ensure that pictures and graphics not lead to misunderstanding. [6] Use hyper text, colors, interaction strategies and other Web communication capabilities to create more attraction. [6] Keep the number of graphics at minimum to avoid increasing download time and making difficult the accessibility of questionnaires across the sample. [6] Prefer small graphics that will download quickly: individual images should not exceed 5KB in size and single web-page should not exceed 20KB of graphics in total. [12] Include a text only version of the webpage, in addition that with graphics. [12] Use crisp and clear images to benefit users with visual disabilities. Remember to not blur pictures, grey out information or overlap menus. [12] Make sure that users can skip multimedia content without penalty. It is better to avoid multimedia and audio clips with graphics if users have to download the plug ins to complete the questionnaire. [12] Use logotypes in order to reduce item non-response and the tendency of users to choose the middle point of a rating scale. [12] The use of graphical symbols or words is useful to indicate user’s progress through questionnaire. [2] Avoid graphics and symbols that require significant increase in computer memory. [14]	It is better to use large and bright symbols to identify the starting point on each page. [14] Use graphical languages to facilitate the logical flow of the questionnaire. [16] Consider the different meanings of symbols among different cultures. [16] Use the graphic only to increase the user’s motivation, download speed improvement and tiredness reduction. [11] Ensure that pictures and graphics not lead to misunderstanding. [6] Use hyper text, colors, interaction strategies and other Web communication capabilities to create more attraction. [6] Keep the number of graphics at minimum to avoid increasing download time and making difficult the accessibility of questionnaires across the sample. [6] Prefer small graphics that will download quickly: individual images should not exceed 5KB in size and single web-page should not exceed 20KB of graphics in total. [12] Include a text only version of the webpage, in addition that with graphics. [12] Use crisp and clear images to benefit users with visual disabilities. Remember to not blur pictures, grey out information or overlap menus. [12] Make sure that users can skip multimedia content without penalty. It is better to avoid multimedia and audio clips with graphics if users have to download the plug ins to complete the questionnaire. [12] Use logotypes in order to reduce item non-response and the tendency of users to choose the middle point of a rating scale. [12] The use of graphical symbols or words is useful to indicate user’s progress through questionnaire. [2] Avoid graphics and symbols that require significant increase in computer memory. [14]	It is better to use large and bright symbols to identify the starting point on each page. [14] Use graphical languages to facilitate the logical flow of the questionnaire. [16] Consider the different meanings of symbols among different cultures. [16] Use the graphic only to increase the user’s motivation, download speed improvement and tiredness reduction. [11] Ensure that pictures and graphics not lead to misunderstanding. [6] Use hyper text, colors, interaction strategies and other Web communication capabilities to create more attraction. [6] Keep the number of graphics at minimum to avoid increasing download time and making difficult the accessibility of questionnaires across the sample. [6] Prefer small graphics that will download quickly: individual images should not exceed 5KB in size and single web-page should not exceed 20KB of graphics in total. [12] Include a text only version of the webpage, in addition that with graphics. [12] Use crisp and clear images to benefit users with visual disabilities. Remember to not blur pictures, grey out information or overlap menus. [12] Make sure that users can skip multimedia content without penalty. It is better to avoid multimedia and audio clips with graphics if users have to download the plug ins to complete the questionnaire. [12] Use logotypes in order to reduce item non-response and the tendency of users to choose the middle point of a rating scale. [12] The use of graphical symbols or words is useful to indicate user’s progress through questionnaire. [2] Avoid graphics and symbols that require significant increase in computer memory. [14]
	Tables and frame	Use tables to present ordinal responses of several constructs within a single question. [14] Do not use frames, since they can make pages difficult to read and print, increase load time, and cause problems for respondents who use assistive technology. [9] Avoid frame technology, because it distracts the respondents from answering the questions. [12]	Use tables to present ordinal responses of several constructs within a single question. [14] Do not use frames, since they can make pages difficult to read and print, increase load time, and cause problems for respondents who use assistive technology. [9] Avoid frame technology, because it distracts the respondents from answering the questions. [12]	Use tables to present ordinal responses of several constructs within a single question. [14] Do not use frames, since they can make pages difficult to read and print, increase load time, and cause problems for respondents who use assistive technology. [9] Avoid frame technology, because it distracts the respondents from answering the questions. [12]	Use tables to present ordinal responses of several constructs within a single question. [14] Do not use frames, since they can make pages difficult to read and print, increase load time, and cause problems for respondents who use assistive technology. [9] Avoid frame technology, because it distracts the respondents from answering the questions. [12]
	Visual analogue scale	Do not include initial starting position for the cursor, in order to reduce the risk of bias within the subjective assessment. [14] The line should start blank and a mark appear where the scale is first tapped. Then the mark may be dragged with the cursor to adjust it, or the position of a second tap may replace the first, or both. [11]	Do not include initial starting position for the cursor, in order to reduce the risk of bias within the subjective assessment. [11] The line should start blank and a mark appear where the scale is first tapped. Then the mark may be dragged with the cursor to adjust it, or the position of a second tap may replace the first, or both. [11]	Do not include initial starting position for the cursor, in order to reduce the risk of bias within the subjective assessment. [11] The line should start blank and a mark appear where the scale is first tapped. Then the mark may be dragged with the cursor to adjust it, or the position of a second tap may replace the first, or both. [11]	Do not include initial starting position for the cursor, in order to reduce the risk of bias within the subjective assessment. [11] The line should start blank and a mark appear where the scale is first tapped. Then the mark may be dragged with the cursor to adjust it, or the position of a second tap may replace the first, or both. [11]
	Matrix questions	Matrix questions must be used sparingly to condense and simplify a question if it involves many response options. [11] Do not use matrix questions in tabular form in order to avoid that respondents might possibly choose those answers that are easiest to reach with the mouse, rather than those buttons that express their real opinion. [12]	Matrix questions must be used sparingly to condense and simplify a question if it involves many response options. [14] Do not use matrix questions in tabular form in order to avoid that respondents might possibly choose those answers that are easiest to reach with the mouse, rather than those buttons that express their real opinion. [12]	Matrix questions must be used sparingly to condense and simplify a question if it involves many response options. [14] Do not use matrix questions in tabular form in order to avoid that respondents might possibly choose those answers that are easiest to reach with the mouse, rather than those buttons that express their real opinion. [12]	Matrix questions must be used sparingly to condense and simplify a question if it involves many response options. [14] Do not use matrix questions in tabular form in order to avoid that respondents might possibly choose those answers that are easiest to reach with the mouse, rather than those buttons that express their real opinion. [12]
	Drop down boxes	Drop down boxes should be used only when answering process is simplified and should be identified with click here. [14] Avoid drop-down selections, because the options are not available when the selection is being reviewed by the patient. [16] Use drop-down boxes sparingly, only when very long lists of response options are required. [11] Enhance drop-down boxes’ usability by incorporating type-ahead look up and avoiding requirement for, or possibility of, multiple selections. [12] It is important that first option in the drop-down box is not visible by default since this can lead respondents and that visual clues to indicate how the drop-box is used are clear and visible. [12]	Drop down boxes should be used only when answering process is simplified and should be identified with click here. [12] Avoid drop-down selections, because the options are not available when the selection is being reviewed by the patient. [16] Use drop-down boxes sparingly, only when very long lists of response options are required. [11] Enhance drop-down boxes’ usability by incorporating type-ahead look up and avoiding requirement for, or possibility of, multiple selections. [12] It is important that first option in the drop-down box is not visible by default since this can lead respondents and that visual clues to indicate how the drop-box is used are clear and visible. [12]	Drop down boxes should be used only when answering process is simplified and should be identified with click here. [12] Avoid drop-down selections, because the options are not available when the selection is being reviewed by the patient. [16] Use drop-down boxes sparingly, only when very long lists of response options are required. [11] Enhance drop-down boxes’ usability by incorporating type-ahead look up and avoiding requirement for, or possibility of, multiple selections. [12] It is important that first option in the drop-down box is not visible by default since this can lead respondents and that visual clues to indicate how the drop-box is used are clear and visible. [12]	Drop down boxes should be used only when answering process is simplified and should be identified with click here. [12] Avoid drop-down selections, because the options are not available when the selection is being reviewed by the patient. [16] Use drop-down boxes sparingly, only when very long lists of response options are required. [11] Enhance drop-down boxes’ usability by incorporating type-ahead look up and avoiding requirement for, or possibility of, multiple selections. [12] It is important that first option in the drop-down box is not visible by default since this can lead respondents and that visual clues to indicate how the drop-box is used are clear and visible. [12]
	Radio buttons	In compares to entry boxes, the use of radio buttons may decrease the likelihood of missing data. [12] Radio buttons reduce missing items, whereas text box entries increase the quality of responses. [9] The area available to be tapped must be explicitly indicated, as with the lower option. [5] When the radio button is selected, the whole button must be highlighted, and the text must remain visible. [11] Only one radio button within any given group of radio buttons can be selected at a time. [11] Provide clear instructions when using radio buttons, especially for users with limited computer experience, who often do not know how to provide and/or change their responses. [12]	In compares to entry boxes, the use of radio buttons may decrease the likelihood of missing data. [12] Radio buttons reduce missing items, whereas text box entries increase the quality of responses. [9] The area available to be tapped must be explicitly indicated, as with the lower option. [5] When the radio button is selected, the whole button must be highlighted, and the text must remain visible. [11] Only one radio button within any given group of radio buttons can be selected at a time. [11] Provide clear instructions when using radio buttons, especially for users with limited computer experience, who often do not know how to provide and/or change their responses. [12]	In compares to entry boxes, the use of radio buttons may decrease the likelihood of missing data. [12] Radio buttons reduce missing items, whereas text box entries increase the quality of responses. [9] The area available to be tapped must be explicitly indicated, as with the lower option. [5] When the radio button is selected, the whole button must be highlighted, and the text must remain visible. [11] Only one radio button within any given group of radio buttons can be selected at a time. [11] Provide clear instructions when using radio buttons, especially for users with limited computer experience, who often do not know how to provide and/or change their responses. [12]	In compares to entry boxes, the use of radio buttons may decrease the likelihood of missing data. [12] Radio buttons reduce missing items, whereas text box entries increase the quality of responses. [9] The area available to be tapped must be explicitly indicated, as with the lower option. [5] When the radio button is selected, the whole button must be highlighted, and the text must remain visible. [11] Only one radio button within any given group of radio buttons can be selected at a time. [11] Provide clear instructions when using radio buttons, especially for users with limited computer experience, who often do not know how to provide and/or change their responses. [12]
	Check buttons	Use short entry boxes, rather than long entry boxes in order to reduce the likelihood of invalid responses. [12] In case of multiple selections present the alternatives as boxes to be tapped, in order to make the area larger, and to explicit the “none of the above” option. [9] Spin button must have a large area to be tapped, it should not start at zero, but with a blank or null value. [11] Allow many selections within a set when multiple response options can be selected. [11] Clear instructions should be provided when using check boxes, in order to consent the participation of all users, including users with disabilities. [12]	Use short entry boxes, rather than long entry boxes in order to reduce the likelihood of invalid responses. [12] In case of multiple selections present the alternatives as boxes to be tapped, in order to make the area larger, and to explicit the “none of the above” option. [9] Spin button must have a large area to be tapped, it should not start at zero, but with a blank or null value. [11] Allow many selections within a set when multiple response options can be selected. [11] Clear instructions should be provided when using check boxes, in order to consent the participation of all users, including users with disabilities. [12]	Use short entry boxes, rather than long entry boxes in order to reduce the likelihood of invalid responses. [12] In case of multiple selections present the alternatives as boxes to be tapped, in order to make the area larger, and to explicit the “none of the above” option. [9] Spin button must have a large area to be tapped, it should not start at zero, but with a blank or null value. [11] Allow many selections within a set when multiple response options can be selected. [11] Clear instructions should be provided when using check boxes, in order to consent the participation of all users, including users with disabilities. [12]	Use short entry boxes, rather than long entry boxes in order to reduce the likelihood of invalid responses. [12] In case of multiple selections present the alternatives as boxes to be tapped, in order to make the area larger, and to explicit the “none of the above” option. [9] Spin button must have a large area to be tapped, it should not start at zero, but with a blank or null value. [11] Allow many selections within a set when multiple response options can be selected. [11] Clear instructions should be provided when using check boxes, in order to consent the participation of all users, including users with disabilities. [12]
INFORMATIC ACCESSIBILITY	Questionnaire distribution and login procedures	Use a mixed-mode strategy, (electronic and pen-and-paper questionnaire), to reach respondents without access to the Internet. [12] Inform and encourage the sample to answer, through sending an E-mail to each person or even to a certain group, putting questionnaire link on the web page, using Popup window and brochure distribution. Even sending reminder letters with an appropriate scheduling should be considered. [5] Use a semiautomatic login procedure, including an access code, in order to not decrease response rates and increase data quality. [6] Develop a identification system to control coverage error and highlight the reliability of the test. [5] Restrict the accesses to the questionnaire, using an ID and a password. [16] If the questionnaire is directed to a specific sample, include a registration or login screen. [6] Give a PIN number only to the sample, in order to avoid questionnaire access by other people. [12]	Use a mixed-mode strategy, (electronic and pen-and-paper questionnaire), to reach respondents without access to the Internet. [14] Inform and encourage the sample to answer, through sending an E-mail to each person or even to a certain group, putting questionnaire link on the web page, using Popup window and brochure distribution. Even sending reminder letters with an appropriate scheduling should be considered. [5] Use a semiautomatic login procedure, including an access code, in order to not decrease response rates and increase data quality. [6] The distribution of web survey to anyone willing to complete them can be considered a form of indirect mailing. Such surveys are prone to various form of bias. [5] Develop a identification system to control coverage error and highlight the reliability of the test. [5] Restrict the accesses to the questionnaire, using an ID and a password. [16] If the questionnaire is directed to a specific sample, include a registration or login screen. [6] Give a PIN number only to the sample, in order to avoid questionnaire access by other people. [12]	Use a mixed-mode strategy, (electronic and pen-and-paper questionnaire), to reach respondents without access to the Internet. [14] Inform and encourage the sample to answer, through sending an E-mail to each person or even to a certain group, putting questionnaire link on the web page, using Popup window and brochure distribution. Even sending reminder letters with an appropriate scheduling should be considered. [5] Use a semiautomatic login procedure, including an access code, in order to not decrease response rates and increase data quality. [6] The distribution of web survey to anyone willing to complete them can be considered a form of indirect mailing. Such surveys are prone to various form of bias. [5] Develop a identification system to control coverage error and highlight the reliability of the test. [5] Restrict the accesses to the questionnaire, using an ID and a password. [16] If the questionnaire is directed to a specific sample, include a registration or login screen. [6] Give a PIN number only to the sample, in order to avoid questionnaire access by other people. [12]	Use a mixed-mode strategy, (electronic and pen-and-paper questionnaire), to reach respondents without access to the Internet. [14] Inform and encourage the sample to answer, through sending an E-mail to each person or even to a certain group, putting questionnaire link on the web page, using Popup window and brochure distribution. Even sending reminder letters with an appropriate scheduling should be considered. [5] Manage deployment process when email address for mobile surveys is different from main panel email address. [6] Use a semiautomatic login procedure, including an access code, in order to not decrease response rates and increase data quality. [10] The distribution of web survey to anyone willing to complete them can be considered a form of indirect mailing. Such surveys are prone to various form of bias. [5] Develop a identification system to control coverage error and highlight the reliability of the test. [5] Restrict the accesses to the questionnaire, using an ID and a password. [16] If the questionnaire is directed to a specific sample, include a registration or login screen. [6] Give a PIN number only to the sample, in order to avoid questionnaire access by other people. [12]
	Cover letter	Cover letter should state the objective of the survey and highlight why potential respondents were selected. [14] Provide an estimate of the time required to complete the questionnaire. [9] Use a personalize cover letter to increases survey response rate. [9]	Cover letter should state the objective of the survey and highlight why potential respondents were selected. [5, 9] Provide an estimate of the time required to complete the questionnaire. [9] Potential respondents can be sent an electronic cover letter either with the initial or reminder questionnaires attached or with a link to the Internet-based questionnaire. Alternatively, the cover letter and questionnaire can be posted on the Web. [9] Use a personalize cover letter to increases survey response rate. [9]	Cover letter should state the objective of the survey and highlight why potential respondents were selected. [5, 9] Provide an estimate of the time required to complete the questionnaire. [9] Potential respondents can be sent an electronic cover letter either with the initial or reminder questionnaires attached or with a link to the Internet-based questionnaire. Alternatively, the cover letter and questionnaire can be posted on the Web. [9] Use a personalize cover letter to increases survey response rate. [9]	Cover letter should state the objective of the survey and highlight why potential respondents were selected. [5, 9] Provide an estimate of the time required to complete the questionnaire. [9] Use a personalize cover letter to increases survey response rate. [9]
	Thank you page and user’s feedback	Take in consideration the email correspondence from respondents, because it can be an important source of information. [5, 9] Remember to read and answer to feedback messages sanded by the patients. [5] At the end of the questionnaire, remember to thank the users for their collaboration, using a gentle and friendly tone. [11]	Take in consideration the email correspondence from respondents, because it can be an important source of information. [12] Remember to read and answer to feedback messages sanded by the patients. [5] At the end of the questionnaire, remember to thank the users for their collaboration, using a gentle and friendly tone. [11]	Take in consideration the email correspondence from respondents, because it can be an important source of information. [12] Remember to read and answer to feedback messages sanded by the patients. [5] At the end of the questionnaire, remember to thank the users for their collaboration, using a gentle and friendly tone. [11]	Take in consideration the email correspondence from respondents, because it can be an important source of information. [12] Remember to read and answer to feedback messages sanded by the patients. [5] At the end of the questionnaire, remember to thank the users for their collaboration, using a gentle and friendly tone. [11]
	Confirmation message	Include confirmation message that an action has been successfully completed where there is a significant possibility that it will not do so. [12]	Include confirmation message that an action has been successfully completed where there is a significant possibility that it will not do so. [11]	Include confirmation message that an action has been successfully completed where there is a significant possibility that it will not do so. [11]	Include confirmation message that an action has been successfully completed where there is a significant possibility that it will not do so. [11]
	Timeout	Timeout during answering must be permitted. [11]	Timeout during answering must be permitted. [6]	Timeout during answering must be permitted. [6]	Timeout during answering must be permitted. [6]
	Progress indicators	Use a progress indicator in order to reduce respondent loss. [6] Insert words and/or symbols that accurately communicate progress towards completion, in order to avoid premature termination. [5] Insert a simple progress indicator to show users how far they are through the sequence, especially for long quality of life questionnaires. [16] Regulate the progress process, either by making navigation decisions automatically on the basis of data already available within the application, or by presenting the options in a form that is completely straightforward for the patient. [11] Design progress process in a way that the user does not consider it as an endless processing. [11] Give users the information concerning the duration of the questionnaire: it should be clear to how many questions remain to be answered. [6] Place the navigational buttons at the bottom of the screen, ensuring that the user would have to scroll down the side in order to read all of the information on a page. [14]	Use a progress indicator in order to reduce respondent loss. [18] Insert words and/or symbols that accurately communicate progress towards completion, in order to avoid premature termination. [5] Insert a simple progress indicator to show users how far they are through the sequence, especially for long quality of life questionnaires. [16] Regulate the progress process, either by making navigation decisions automatically on the basis of data already available within the application, or by presenting the options in a form that is completely straightforward for the patient. [11] Design progress process in a way that the user does not consider it as an endless processing. [11] Give users the information concerning the duration of the questionnaire: it should be clear to how many questions remain to be answered. [6] Place the navigational buttons at the bottom of the screen, ensuring that the user would have to scroll down the side in order to read all of the information on a page. [14]	Use a progress indicator in order to reduce respondent loss. [18] Insert words and/or symbols that accurately communicate progress towards completion, in order to avoid premature termination. [5] Insert a simple progress indicator to show users how far they are through the sequence, especially for long quality of life questionnaires. [16] Regulate the progress process, either by making navigation decisions automatically on the basis of data already available within the application, or by presenting the options in a form that is completely straightforward for the patient. [11] Design progress process in a way that the user does not consider it as an endless processing. [11] Give users the information concerning the duration of the questionnaire: it should be clear to how many questions remain to be answered. [6] Place the navigational buttons at the bottom of the screen, ensuring that the user would have to scroll down the side in order to read all of the information on a page. [14]	Use a progress indicator in order to reduce respondent loss. [18] Insert words and/or symbols that accurately communicate progress towards completion, in order to avoid premature termination. [5] Insert a simple progress indicator to show users how far they are through the sequence, especially for long quality of life questionnaires. [16] Regulate the progress process, either by making navigation decisions automatically on the basis of data already available within the application, or by presenting the options in a form that is completely straightforward for the patient. [11] Design progress process in a way that the user does not consider it as an endless processing. [11] Give users the information concerning the duration of the questionnaire: it should be clear to how many questions remain to be answered. [6] Place the navigational buttons at the bottom of the screen, ensuring that the user would have to scroll down the side in order to read all of the information on a page. [14]
	One page and multiple page design	Think carefully to which type of page design choose: one-page design reflects the conventional formula where there is no interaction with the respondent during questionnaire completion; on the other hand multiple-page design increases the controls on non response questions, and also increases the risk of abandoning the questionnaire. [18] Try to include only one question for page; if bandwidth is not enough, design questionnaire flow so that the users’ attention is not diverted by other cognitive processes. [2]	Think carefully to which type of page design choose: one-page design reflects the conventional formula where there is no interaction with the respondent during questionnaire completion; on the other hand multiple-page design increases the controls on non response questions, and also increases the risk of abandoning the questionnaire. [14] Try to include only one question for page; if bandwidth is not enough, design questionnaire flow so that the users’ attention is not diverted by other cognitive processes. [2]	Think carefully to which type of page design choose: one-page design reflects the conventional formula where there is no interaction with the respondent during questionnaire completion; on the other hand multiple-page design increases the controls on non response questions, and also increases the risk of abandoning the questionnaire. [14] Try to include only one question for page; if bandwidth is not enough, design questionnaire flow so that the users’ attention is not diverted by other cognitive processes. [2]	Think carefully to which type of page design choose: one-page design reflects the conventional formula where there is no interaction with the respondent during questionnaire completion; on the other hand multiple-page design increases the controls on non response questions, and also increases the risk of abandoning the questionnaire. [14] Try to include only one question for page; if bandwidth is not enough, design questionnaire flow so that the users’ attention is not diverted by other cognitive processes. [2] Consider whether to use paging of questions to separate pages or one page questionnaires. In the case of online questionnaires, paging causes undesirable download delays. For touch screens we found it better to avoid paging due to these delays, since scrolling is easy. On the other hand, for conventional screens, the tradeoff between download delays and more cumbersome interaction needs to be considered. [14]
	Phraseology	Question Should focus on a single construct. [17] Avoid absolute terms, abbreviations and complex terminology. [9] The perspective from which questions should be addressed must be clarified, particularly for questions about attitudes. [9] Every question stem should include a clear request for either single or multiple responses and indicate the desired notation. [9] Questions must be formulated in a way that minimizes the need to reread portions in order to comprehend to response task. [9] Questions should contain no more than 20 words, and must be composed by familiar and simple words, and precise, consistent, grammatically correct sentences. [16] In questions’ composition avoid: acronyms, abbreviations, slang, jargon, proverbs, technical expressions, colloquial expressions, popular sayings, long alternatives as possible responses, different alternatives that could all be true, words which imply different meaning to different people, a lot of information carrying words, and loaded or provocative words. [12] Questions should be phrased so that they avoid being: double-barrelled; double-negative; hypothetical; negative; leading or biasing; two-edged. [12] Compose questions in the present tense using the active voice. [12] Explain users the meanings initials or acronyms. [12] Use general standards for the correct formulation of questions. [12] Write concise and precisely formulated questions that can be understood in the same way by all respondents. [2] Question’s wording should not try respondents’ abilities: do not ask the user to answer questions on concepts unknown to him. [14] One question must not contain too many concepts. [14] Questions should correspond to the thematic reference. [14] Do not use question structures that have known measurement problems on paper questionnaires. [14] Limit the amount of text in the question, in order to have more space for answer categories and avoid scrolling. [14] Don’t state your scale in the question. [10] Remove superfluous words: get to the point. [10]	Question Should focus on a single construct. [10] Avoid absolute terms, abbreviations and complex terminology. [9] The perspective from which questions should be addressed must be clarified, particularly for questions about attitudes. [9] Every question stem should include a clear request for either single or multiple responses and indicate the desired notation. [9] Questions must be formulated in a way that minimizes the need to reread portions in order to comprehend to response task. [9] Questions should contain no more than 20 words, and must be composed by familiar and simple words, and precise, consistent, grammatically correct sentences. [16] In questions’ composition avoid: acronyms, abbreviations, slang, jargon, proverbs, technical expressions, colloquial expressions, popular sayings, long alternatives as possible responses, different alternatives that could all be true, words which imply different meaning to different people, a lot of information carrying words, and loaded or provocative words. [12] Questions should be phrased so that they avoid being: double-barrelled; double-negative; hypothetical; negative; leading or biasing; two-edged. [12] Compose questions in the present tense using the active voice. [12] Explain users the meanings initials or acronyms. [12] Use general standards for the correct formulation of questions. [12] Write concise and precisely formulated questions that can be understood in the same way by all respondents. [2] Question’s wording should not try respondents’ abilities: do not ask the user to answer questions on concepts unknown to him. [14] One question must not contain too many concepts. [14] Questions should correspond to the thematic reference. [14] Do not use question structures that have known measurement problems on paper questionnaires. [14] Limit the amount of text in the question, in order to have more space for answer categories and avoid scrolling. [14] Don’t state your scale in the question. [10] Remove superfluous words: get to the point. [10]	Question Should focus on a single construct. [10] Avoid absolute terms, abbreviations and complex terminology. [9] The perspective from which questions should be addressed must be clarified, particularly for questions about attitudes. [9] Every question stem should include a clear request for either single or multiple responses and indicate the desired notation. [9] Questions must be formulated in a way that minimizes the need to reread portions in order to comprehend to response task. [9] Questions should contain no more than 20 words, and must be composed by familiar and simple words, and precise, consistent, grammatically correct sentences. [16] In questions’ composition avoid: acronyms, abbreviations, slang, jargon, proverbs, technical expressions, colloquial expressions, popular sayings, long alternatives as possible responses, different alternatives that could all be true, words which imply different meaning to different people, a lot of information carrying words, and loaded or provocative words. [12] Questions should be phrased so that they avoid being: double-barrelled; double-negative; hypothetical; negative; leading or biasing; two-edged. [12] Compose questions in the present tense using the active voice. [12] Explain users the meanings initials or acronyms. [12] Use general standards for the correct formulation of questions. [12] Write concise and precisely formulated questions that can be understood in the same way by all respondents. [2] Question’s wording should not try respondents’ abilities: do not ask the user to answer questions on concepts unknown to him. [14] One question must not contain too many concepts. [14] Questions should correspond to the thematic reference. [14] Do not use question structures that have known measurement problems on paper questionnaires. [14] Limit the amount of text in the question, in order to have more space for answer categories and avoid scrolling. [14] Don’t state your scale in the question. [10] Remove superfluous words: get to the point. [10]	Question Should focus on a single construct. [10] Avoid absolute terms, abbreviations and complex terminology. [9] The perspective from which questions should be addressed must be clarified, particularly for questions about attitudes. [9] Every question stem should include a clear request for either single or multiple responses and indicate the desired notation. [9] Questions must be formulated in a way that minimizes the need to reread portions in order to comprehend to response task. [9] Questions should contain no more than 20 words, and must be composed by familiar and simple words, and precise, consistent, grammatically correct sentences. [16] In questions’ composition avoid: acronyms, abbreviations, slang, jargon, proverbs, technical expressions, colloquial expressions, popular sayings, long alternatives as possible responses, different alternatives that could all be true, words which imply different meaning to different people, a lot of information carrying words, and loaded or provocative words. [12] Questions should be phrased so that they avoid being: double-barrelled; double-negative; hypothetical; negative; leading or biasing; two-edged. [12] Compose questions in the present tense using the active voice. [12] Explain users the meanings initials or acronyms. [12] Use general standards for the correct formulation of questions. [12] Write concise and precisely formulated questions that can be understood in the same way by all respondents. [2] Question’s wording should not try respondents’ abilities: do not ask the user to answer questions on concepts unknown to him. [14] One question must not contain too many concepts. [14] Questions should correspond to the thematic reference. [14] Do not use question structures that have known measurement problems on paper questionnaires. [14] Limit the amount of text in the question, in order to have more space for answer categories and avoid scrolling. [14] Don’t state your scale in the question. [10] Remove superfluous words: get to the point. [10]
	Language and wording	Pay attention to the language, because it influences directly the response formats, and so the response rate. [10] Present all information in the patient’s language, including any warning screens that may appear. Remember that some languages are more verbose than others. [9] Questions must be formulated in a socially and culturally sensitive manner, nonjudgmental and unbiased. [11] Use neutral tone for questions requesting users to rank items or elicit their opinions. [9] Use non-threatening language for provide missing item requests. [9] Additional information requested should be based on the patient’s own immediate situation. [16] Do not use inessential and inquisitive questions. [11] Asking for answer must be just in needful condition, although more questions lead to more perfect and clear information. [6] Use more indirect-oblique statements for questions on attitudes about particular topics. [6]	Pay attention to the language, because it influences directly the response formats, and so the response rate. [12] Present all information in the patient’s language, including any warning screens that may appear. Remember that some languages are more verbose than others. [9] Questions must be formulated in a socially and culturally sensitive manner, nonjudgmental and unbiased. [11] Use neutral tone for questions requesting users to rank items or elicit their opinions. [9] Use non-threatening language for provide missing item requests. [9] Additional information requested should be based on the patient’s own immediate situation. [16] Do not use inessential and inquisitive questions. [11] Asking for answer must be just in needful condition, although more questions lead to more perfect and clear information. [6] Use more indirect-oblique statements for questions on attitudes about particular topics. [6]	Pay attention to the language, because it influences directly the response formats, and so the response rate. [12] Present all information in the patient’s language, including any warning screens that may appear. Remember that some languages are more verbose than others. [9] Questions must be formulated in a socially and culturally sensitive manner, nonjudgmental and unbiased. [11] Use neutral tone for questions requesting users to rank items or elicit their opinions. [9] Use non-threatening language for provide missing item requests. [9] Additional information requested should be based on the patient’s own immediate situation. [16] Do not use inessential and inquisitive questions. [11] Asking for answer must be just in needful condition, although more questions lead to more perfect and clear information. [6] Use more indirect-oblique statements for questions on attitudes about particular topics. [6]	Pay attention to the language, because it influences directly the response formats, and so the response rate. [12] Present all information in the patient’s language, including any warning screens that may appear. Remember that some languages are more verbose than others. [9] Questions must be formulated in a socially and culturally sensitive manner, nonjudgmental and unbiased. [11] Use neutral tone for questions requesting users to rank items or elicit their opinions. [9] Use non-threatening language for provide missing item requests. [9] Additional information requested should be based on the patient’s own immediate situation. [16] Do not use inessential and inquisitive questions. [11] Asking for answer must be just in needful condition, although more questions lead to more perfect and clear information. [6] Use more indirect-oblique statements for questions on attitudes about particular topics. [6] Choose app questionnaire when the topic is personal and delicate. [12]
	Multiple choice	Double or triple banking of answer choices should be avoided. [15] Limitation of choices must be indicated (5 to 10 choices). [16] Use double-banking of answer when the number of answer choices exceeds the number that can be displayed in a single column on one screen. [6] Limit the number of answer categories. If is possible don’t exceed ten answer categories. [14] Limit the amount of text in each individual answer category. [10]	Double or triple banking of answer choices should be avoided. [10] Limitation of choices must be indicated (5 to 10 choices). [16] Use double-banking of answer when the number of answer choices exceeds the number that can be displayed in a single column on one screen. [6] Limit the number of answer categories. If is possible don’t exceed ten answer categories. [14] Limit the amount of text in each individual answer category. [10]	Double or triple banking of answer choices should be avoided. [10] Limitation of choices must be indicated (5 to 10 choices). [16] Use double-banking of answer when the number of answer choices exceeds the number that can be displayed in a single column on one screen. [6] Limit the number of answer categories. If is possible don’t exceed ten answer categories. [14] Limit the amount of text in each individual answer category. [10]	Double or triple banking of answer choices should be avoided. [10] Limitation of choices must be indicated (5 to 10 choices). [16] Use double-banking of answer when the number of answer choices exceeds the number that can be displayed in a single column on one screen. [6] Limit the number of answer categories. If is possible don’t exceed ten answer categories. [14] Limit the amount of text in each individual answer category. [10]
	Skip/ Filter questions	When skip patterns are used, apply a redundant visual change to highlight the questionnaire’s flow and gain user’s compliance. [10] Use skip questions to determine, on the basis of an individual respondent’s answer, which of the following questions the user should jump to when question path is response directed. [16] Make skip questions explicit, separate them from all other question types, include a training instruction, and use reminder instructions within the remainder of the questionnaire. [12] Use filter questions to increase the quality of data and avoid wrong answers. [12] Include skip directions to encourage users to mark the answers and click to the next applicable question. [14] Include a jump to page scroll bar at the top of every page, to make the users able to see how far along they are in the questionnaire flow, and to make them able to jump and change previous answers if necessary. [14]	When skip patterns are used, apply a redundant visual change to highlight the questionnaire’s flow and gain user’s compliance. [18] Use skip questions to determine, on the basis of an individual respondent’s answer, which of the following questions the user should jump to when question path is response directed. [16] Make skip questions explicit, separate them from all other question types, include a training instruction, and use reminder instructions within the remainder of the questionnaire. [12] Use filter questions to increase the quality of data and avoid wrong answers. [12] Include skip directions to encourage users to mark the answers and click to the next applicable question. [14] Include a jump to page scroll bar at the top of every page, to make the users able to see how far along they are in the questionnaire flow, and to make them able to jump and change previous answers if necessary. [14]	When skip patterns are used, apply a redundant visual change to highlight the questionnaire’s flow and gain user’s compliance. [18] Use skip questions to determine, on the basis of an individual respondent’s answer, which of the following questions the user should jump to when question path is response directed. [16] Make skip questions explicit, separate them from all other question types, include a training instruction, and use reminder instructions within the remainder of the questionnaire. [12] Use filter questions to increase the quality of data and avoid wrong answers. [12] Include skip directions to encourage users to mark the answers and click to the next applicable question. [14] Include a jump to page scroll bar at the top of every page, to make the users able to see how far along they are in the questionnaire flow, and to make them able to jump and change previous answers if necessary. [14]	When skip patterns are used, apply a redundant visual change to highlight the questionnaire’s flow and gain user’s compliance. [18] Use skip questions to determine, on the basis of an individual respondent’s answer, which of the following questions the user should jump to when question path is response directed. [16] Make skip questions explicit, separate them from all other question types, include a training instruction, and use reminder instructions within the remainder of the questionnaire. [12] Use filter questions to increase the quality of data and avoid wrong answers. [12] Include skip directions to encourage users to mark the answers and click to the next applicable question. [14] Include a jump to page scroll bar at the top of every page, to make the users able to see how far along they are in the questionnaire flow, and to make them able to jump and change previous answers if necessary. [14]
	Invitation and reminders		Use reminder letters and telephone contact, in order to increase response rates. [18] Use 3 follow up weaves: an initial reminder postcard sent 1 week after the initial mailing of the questionnaire to the entire sample, and 2 reminders (a letter plus replacement questionnaire) sent at 3 and 7 weeks to non respondent, with the final letter and replacement questionnaire sent by certified mail. [9] Send a pre-notification to prospective respondents in order to increase response rate and speed of response to survey. [9] Use the e-mail invitation in order to elicit responses to a Web survey. [5] Undertake multiple attempts to contact potential respondents, through pre notifications, reminders and replacement surveys, thank you notes. [5] Send an announcement prior to the survey, in order to increase response time. [5] The response rate can be increased through the use of random encouragement, namely a personal invitation via email to complete the survey. [5]	Use reminder letters and telephone contact, in order to increase response rates. [5] Use 3 follow up weaves: an initial reminder postcard sent 1 week after the initial mailing of the questionnaire to the entire sample, and 2 reminders (a letter plus replacement questionnaire) sent at 3 and 7 weeks to non respondent, with the final letter and replacement questionnaire sent by certified mail. [9] Send a pre-notification to prospective respondents in order to increase response rate and speed of response to survey. [9] Use the e-mail invitation in order to elicit responses to a Web survey. [5] Undertake multiple attempts to contact potential respondents, through pre notifications, reminders and replacement surveys, thank you notes. [5] Send an announcement prior to the survey, in order to increase response time. [5] The response rate can be increased through the use of random encouragement, namely a personal invitation via email to complete the survey. [5]
	Instructions	Include operational definitions before potentially ambiguous questions. [5] Include clear instructions to skip non applicable questions. [9] Instructions must be placed exactly where the information is needed. [9] Include special instructions (only if those are essential) as a part of the question statement. [16] Separate optional or occasionally needed instructions from the question statement, using font or symbol instructions. [16] Include special guidance instruction in the normal flow of the questionnaire and not separate them from questions. [16] Help user to follow the questionnaire flow, placing instruction for determining eligibility for responding to a section or other major efforts inside navigational guides. [16] Unless a branching instruction depends on it, do not require users to provide an answer to each question before being allowed to answer any subsequent question. [16] Avoid excessive use of check all that apply questions because of the tendency of respondents to satisfied and choose earlier listed answer choices. [16] Definitions, explanations, and instructions in response path must be placed exactly where needed by the respondent. [16] Instruction must be constructed thinking about population need and characteristics. [16] Warnings of unreasonable values must be used only if necessary: avoid them when numeric options are presented as a multi-choice response. [16] If range or logic checks are necessary, include a message that state why there is a warning, and what the patient should do. [11] Make all necessary information simultaneously available on the screen, for both the questions and the response options. [11] Make clear the guidance context and indicate its place. [11] Explain technical instructions in an understandable way for non-technical people. [6] Make sure that all mechanisms for navigation are clearly identified and easy to find. [12] Make sure that answering instructions are extremely clear, in order to facilitate the completion of the questionnaire. [12] Include a sort of help desk in order to collect users’ difficulties with survey access, instructions, and other survey issues. [1] Include operational instructions as part of each question where the action is to be taken. [1] Include specific technical instructions at the point where they are needed. [20] Include understandable notes to help users answer the questions. [14]	Include operational definitions before potentially ambiguous questions. [14] Include clear instructions to skip non applicable questions. [9] Instructions must be placed exactly where the information is needed. [9] Include special instructions (only if those are essential) as a part of the question statement. [16] Separate optional or occasionally needed instructions from the question statement, using font or symbol instructions. [16] Include special guidance instruction in the normal flow of the questionnaire and not separate them from questions. [16] Help user to follow the questionnaire flow, placing instruction for determining eligibility for responding to a section or other major efforts inside navigational guides. [16] Unless a branching instruction depends on it, do not require users to provide an answer to each question before being allowed to answer any subsequent question. [16] Avoid excessive use of check all that apply questions because of the tendency of respondents to satisfied and choose earlier listed answer choices. [16] Definitions, explanations, and instructions in response path must be placed exactly where needed by the respondent. [16] Instruction must be constructed thinking about population need and characteristics. [16] Warnings of unreasonable values must be used only if necessary: avoid them when numeric options are presented as a multi-choice response. [16] If range or logic checks are necessary, include a message that state why there is a warning, and what the patient should do. [11] Make all necessary information simultaneously available on the screen, for both the questions and the response options. [11] Make clear the guidance context and indicate its place. [11] Include aids in the same place on each page of a questionnaire’s website. [6] Explain technical instructions in an understandable way for non-technical people. [12] Make sure that all mechanisms for navigation are clearly identified and easy to find. [12] Make sure that answering instructions are extremely clear, in order to facilitate the completion of the questionnaire. [12] The access to the survey must be easy: it is better to use a URL embedded with a unique identifier for each respondent. [1] Include a sort of help desk in order to collect users’ difficulties with survey access, instructions, and other survey issues. [1] Include operational instructions as part of each question where the action is to be taken. [1] Include specific technical instructions at the point where they are needed. [20] Include understandable notes to help users answer the questions. [14]	Include operational definitions before potentially ambiguous questions. [14] Include clear instructions to skip non applicable questions. [9] Instructions must be placed exactly where the information is needed. [9] Include special instructions (only if those are essential) as a part of the question statement. [16] Separate optional or occasionally needed instructions from the question statement, using font or symbol instructions. [16] Include special guidance instruction in the normal flow of the questionnaire and not separate them from questions. [16] Help user to follow the questionnaire flow, placing instruction for determining eligibility for responding to a section or other major efforts inside navigational guides. [16] Unless a branching instruction depends on it, do not require users to provide an answer to each question before being allowed to answer any subsequent question. [16] Avoid excessive use of check all that apply questions because of the tendency of respondents to satisfied and choose earlier listed answer choices. [16] Definitions, explanations, and instructions in response path must be placed exactly where needed by the respondent. [16] Instruction must be constructed thinking about population need and characteristics. [16] Warnings of unreasonable values must be used only if necessary: avoid them when numeric options are presented as a multi-choice response. [16] If range or logic checks are necessary, include a message that state why there is a warning, and what the patient should do. [11] Make all necessary information simultaneously available on the screen, for both the questions and the response options. [11] Make clear the guidance context and indicate its place. [11] Include aids in the same place on each page of a questionnaire’s website. [6] Explain technical instructions in an understandable way for non-technical people. [12] Make sure that all mechanisms for navigation are clearly identified and easy to find. [12] Make sure that answering instructions are extremely clear, in order to facilitate the completion of the questionnaire. [12] The access to the survey must be easy: it is better to use a URL embedded with a unique identifier for each respondent. [1] Include a sort of help desk in order to collect users’ difficulties with survey access, instructions, and other survey issues. [1] Include operational instructions as part of each question where the action is to be taken. [1] Include specific technical instructions at the point where they are needed. [20] Include understandable notes to help users answer the questions. [14]	Include operational definitions before potentially ambiguous questions. [14] Include clear instructions to skip non applicable questions. [9] Instructions must be placed exactly where the information is needed. [9] Include special instructions (only if those are essential) as a part of the question statement. [16] Separate optional or occasionally needed instructions from the question statement, using font or symbol instructions. [16] Include special guidance instruction in the normal flow of the questionnaire and not separate them from questions. [16] Help user to follow the questionnaire flow, placing instruction for determining eligibility for responding to a section or other major efforts inside navigational guides. [16] Unless a branching instruction depends on it, do not require users to provide an answer to each question before being allowed to answer any subsequent question. [16] Avoid excessive use of check all that apply questions because of the tendency of respondents to satisfied and choose earlier listed answer choices. [16] Definitions, explanations, and instructions in response path must be placed exactly where needed by the respondent. [16] Instruction must be constructed thinking about population need and characteristics. [16] Warnings of unreasonable values must be used only if necessary: avoid them when numeric options are presented as a multi-choice response. [16] If range or logic checks are necessary, include a message that state why there is a warning, and what the patient should do. [11] Make all necessary information simultaneously available on the screen, for both the questions and the response options. [11] Make clear the guidance context and indicate its place. [11] Include aids in the same place on each page of a questionnaire’s website. [6] Explain technical instructions in an understandable way for non-technical people. [12] Make sure that all mechanisms for navigation are clearly identified and easy to find. [12] Make sure that answering instructions are extremely clear, in order to facilitate the completion of the questionnaire. [12] The access to the survey must be easy: it is better to use a URL embedded with a unique identifier for each respondent. [1] Include a sort of help desk in order to collect users’ difficulties with survey access, instructions, and other survey issues. [1] Include operational instructions as part of each question where the action is to be taken. [1] Include specific technical instructions at the point where they are needed. [20] Include understandable notes to help users answer the questions. [14]
	Anonymity and privacy	Measures should be taken to ensure anonymity or at least confidentiality. [14] Survey identification procedures can be considered a breach of respondent anonymity, and thus negatively influencing response rate. It is difficult to achieve full anonymity. Ensure almost confidentially, by informing respondents that their email address will not be recorded with their survey responses, in addition to the fact that survey data will only be analyzed at the aggregate level. [5] Adopt clear, visible, respondent-friendly privacy policies. [5] Inform respondents about their privacy before starting questionnaires. [1]	Measures should be taken to ensure anonymity or at least confidentiality. [15] Survey identification procedures can be considered a breach of respondent anonymity, and thus negatively influencing response rate. It is difficult to achieve full anonymity. Ensure almost confidentially, by informing respondents that their email address will not be recorded with their survey responses, in addition to the fact that survey data will only be analyzed at the aggregate level. [5] Ensure that respondents’ privacy and perception of privacy are protected, especially by encrypting the survey data and preserving anonymity of data received. [5] Don’t contact respondents by email, unless they say it is all right. [12] Adopt clear, visible, respondent-friendly privacy policies. [1] Inform respondents about their privacy before starting questionnaires. [1]	Measures should be taken to ensure anonymity or at least confidentiality. [15] Survey identification procedures can be considered a breach of respondent anonymity, and thus negatively influencing response rate. It is difficult to achieve full anonymity. Ensure almost confidentially, by informing respondents that their email address will not be recorded with their survey responses, in addition to the fact that survey data will only be analyzed at the aggregate level. [5] Ensure that respondents’ privacy and perception of privacy are protected, especially by encrypting the survey data and preserving anonymity of data received. [5] Don’t contact respondents by email, unless they say it is all right. [12] Adopt clear, visible, respondent-friendly privacy policies. [1] Inform respondents about their privacy before starting questionnaires. [1]	Measures should be taken to ensure anonymity or at least confidentiality. [15] Survey identification procedures can be considered a breach of respondent anonymity, and thus negatively influencing response rate. It is difficult to achieve full anonymity. Ensure almost confidentially, by informing respondents that their contacts will not be recorded with their survey responses, in addition to the fact that survey data will only be analyzed at the aggregate level. [5] Ensure that respondents’ privacy and perception of privacy are protected, especially by encrypting the survey data and preserving anonymity of data received. [5] Adopt clear, visible, respondent-friendly privacy policies. [12] Inform respondents about their privacy before starting questionnaires. [1]
	Costs		Consider the fact that users must pay for the time they are online: it is better to distribute the questionnaire in a mixed mode design (email and paper-and-pencil). [15]	Consider the fact that users must pay for the time they are online: it is better to distribute the questionnaire in a mixed mode design (email and paper-and-pencil). [5]	Consider the fact that users must pay for the time they are online: it is better to distribute the questionnaire in a mixed mode design (email and paper-and-pencil). [5]
	Repeated answers		Check the email address of the respondents in order to omit repeated answers in data processing and analyzing. [5] If cookies are used to omit repeated answers, consider the possibility of a new source of non response, resulting from the exclusion of users who restrict placement of such cookies on their computers. [6] If IP number is used to omit repeated answer, consider that some computers may have a multi-user function, and Internet providers can assigne to users different unique identifiers for each dial-up session. [5] Include an automatic “Thank you” message after user has pressed the submit button, in order to avoid multiple press of such button and the multiple transmission of the questionnaire. [5] Check record time, date and addresses to avoid repeated answer sent from certain IP or in short time distance. [5]	If cookies are used to omit repeated answers, consider the possibility of a new source of non response, resulting from the exclusion of users who restrict placement of such cookies on their computers. [6] If IP number is used to omit repeated answer, consider that some computers may have a multi-user function, and Internet providers can assigne to users different unique identifiers for each dial-up session. [5] Include an automatic “Thank you” message after user has pressed the submit button, in order to avoid multiple press of such button and the multiple transmission of the questionnaire. [5] Check record time, date and addresses to avoid repeated answer sent from certain IP or in short time distance. [5]	If cookies are used to omit repeated answers, consider the possibility of a new source of non response, resulting from the exclusion of users who restrict placement of such cookies on their computers. [6] If IP number is used to omit repeated answer, consider that some computers may have a multi-user function, and Internet providers can assigne to users different unique identifiers for each dial-up session. [5] Include an automatic “Thank you” message after user has pressed the submit button, in order to avoid multiple press of such button and the multiple transmission of the questionnaire. [5] Check record time, date and addresses to avoid repeated answer sent from certain IP or in short time distance. [5]
	Screen and type of device	Use devices with 20 cm diagonal screens, if the survey is realized in a clinical setting. [6] When using an on-screen keypad, it is best to set this up a custom layout specifically for the purpose, using only relevant keys. The same principles applies for text keypads. In this way the keypad can be simplified, and the individual keys made larger. [11] Make sure to minimize the changes from keyboard entries to mouse entries, in order to not confuse the user. [11]	Make sure to minimize the changes from keyboard entries to mouse entries, in order to not confuse the user. [14]	Make sure to minimize the changes from keyboard entries to mouse entries, in order to not confuse the user. [14]	Make sure to minimize the changes from keyboard entries to mouse entries, in order to not confuse the user. [14] In mobile surveys remember to consider the four most important things: small screen size, data entry method and interaction style, mobile context and chosen implementation for the questionnaire. [14] Try to identify all devices supported in your data collection software: not only major brands but consider that there are many more and many models. [17] Minimize the skin to maximize the screen size/space. [10]
	User’s computer competence	Estimate the computer equipment respondents may be using as well as their competence with particular programs. [10] Provide a printable version of the questionnaire, if respondents need to prepare information before answering. [5] Build a system virtually usable by all patients eligible for the survey. [16] The data collection system should not exclude older patients, as a consequence of less familiarity with computer system, and a higher probability to have problems such as poor eyesight or tremor. [11] Build a system suitable for a wide range of patients, varying in physical and mental health status, age, and in their experience with technology. [11] Design the system with the less knowledgeable, low-end computer user in mind. [11] Provide an alternative printable format of the questionnaire, and of all referenced articles or documentation. [12] Questionnaires’ technical requirements should be tailored on the target group’s minimal technical requirements, particularly for file sizes, use of graphics and use of advanced programming. [12] Ensure that different devices with different user experiences do not affect the data. [14]	Ensure that potential respondents have access to electronic mail or the Internet. [10] Estimate the computer equipment respondents may be using as well as their competence with particular programs. [9] Web survey must be designed for those with older browser and poorer communication rather than those with state of the art access. [5] Provide a printable version of the questionnaire, if respondents need to prepare information before answering. [16] Build a system virtually usable by all patients eligible for the survey. [16] The data collection system should not exclude older patients, as a consequence of less familiarity with computer system, and a higher probability to have problems such as poor eyesight or tremor. [11] Build a system suitable for a wide range of patients, varying in physical and mental health status, age, and in their experience with technology. [11] Design the system with the less knowledgeable, low-end computer user in mind. [11] Provide an alternative printable format of the questionnaire, and of all referenced articles or documentation. [12] Questionnaires’ technical requirements should be tailored on the target group’s minimal technical requirements, particularly for file sizes, use of graphics and use of advanced programming. [12] Ensure that different devices with different user experiences do not affect the data. [14]	Ensure that potential respondents have access to electronic mail or the Internet. [10] Estimate the computer equipment respondents may be using as well as their competence with particular programs. [9] Web survey must be designed for those with older browser and poorer communication rather than those with state of the art access. [5] Provide a printable version of the questionnaire, if respondents need to prepare information before answering. [16] Build a system virtually usable by all patients eligible for the survey. [16] The data collection system should not exclude older patients, as a consequence of less familiarity with computer system, and a higher probability to have problems such as poor eyesight or tremor. [11] Build a system suitable for a wide range of patients, varying in physical and mental health status, age, and in their experience with technology. [11] Design the system with the less knowledgeable, low-end computer user in mind. [11] Provide an alternative printable format of the questionnaire, and of all referenced articles or documentation. [12] Questionnaires’ technical requirements should be tailored on the target group’s minimal technical requirements, particularly for file sizes, use of graphics and use of advanced programming. [12] Ensure that different devices with different user experiences do not affect the data. [14]	Ensure that potential respondents have access to electronic mail or the Internet. [10] Estimate the computer equipment respondents may be using as well as their competence with particular programs. [9] Web survey must be designed for those with older browser and poorer communication rather than those with state of the art access. [5] Provide a printable version of the questionnaire, if respondents need to prepare information before answering. [16] Build a system virtually usable by all patients eligible for the survey. [16] The data collection system should not exclude older patients, as a consequence of less familiarity with computer system, and a higher probability to have problems such as poor eyesight or tremor. [11] Build a system suitable for a wide range of patients, varying in physical and mental health status, age, and in their experience with technology. [11] Design the system with the less knowledgeable, low-end computer user in mind. [11] Provide an alternative printable format of the questionnaire, and of all referenced articles or documentation. [12] Questionnaires’ technical requirements should be tailored on the target group’s minimal technical requirements, particularly for file sizes, use of graphics and use of advanced programming. [12] Pay attention to the length of answer: users could have some difficult to write a lot of words with touch screen. [14] Pay attention to the type of Smartphone. [15] Ensure that different devices with different user experiences do not affect the data. [15]
	Technical procedures	Ensure that the rule of the thumb must not make burdensome the task. [10] Respondents must not have to reconfigure computers, switch browsers, or download software to complete the questionnaire. [5] Ensure that procedures are as convenient and unobtrusive as possible. [16] If possible, include a date- last- modified notification and a copyright notice in the introductory pages. [11] The total completion time of the questionnaire must be minimized. [12]	Ensure that the rule of the thumb must not make burdensome the task. [17] Prefer email software that offers transformation of URLs into direct links to the Web site, in order to reducing additional actions of the respondents. [5] Respondents must not have to reconfigure computers, switch browsers, or download software to complete the questionnaire. [5] To avoid that respondents have to click to another location, include the questionnaire, if it is short, into an e-mail message. [16] Ensure that procedures are as convenient and unobtrusive as possible. [16] If possible, include a date- last- modified notification and a copyright notice in the introductory pages. [11] Think about slow modem connection when you chose the download time. [12] The total completion time of the questionnaire must be minimized. [14]	Ensure that the rule of the thumb must not make burdensome the task. [17] Prefer email software that offers transformation of URLs into direct links to the Web site, in order to reducing additional actions of the respondents. [5] Respondents must not have to reconfigure computers, switch browsers, or download software to complete the questionnaire. [5] To avoid that respondents have to click to another location, include the questionnaire, if it is short, into an e-mail message. [16] Ensure that procedures are as convenient and unobtrusive as possible. [16] If possible, include a date- last- modified notification and a copyright notice in the introductory pages. [11] Think about slow modem connection when you chose the download time. [12] The total completion time of the questionnaire must be minimized. [14]	Ensure that the rule of the thumb must not make burdensome the task. [17] Respondents must not have to reconfigure devices, switch browsers, or download software to complete the questionnaire. [5] Ensure that procedures are as convenient and unobtrusive as possible. [16] If possible, include a date- last- modified notification and a copyright notice in the introductory pages. [11] Think about slow modem connection when you chose the download time. [12] The total completion time of the questionnaire must be minimized. [14]
	Browser and file size		To avoid that users may not be able to open the questionnaire file, send also a program file attached to the email message. [17] Maintain the file’s imagines as small as possible. [5] Not use browser-specific HTML extensions. [14] Avoid the use of Java and JavaScript, depending on the target population. [14] Design the questionnaire in order that respondents must be able to complete it without the use of a graphic browser if they use a textbased to obtain information from the Web. [14] Not require users to make alterations to their browser’s preferences. [14] Do not use Java Script for online survey. [14]	Not exceed the 60KB of text and graphic content of total web-site. [10] Maintain the file’s imagines as small as possible. [12] Not use browser-specific HTML extensions. [14] Avoid the use of Java and JavaScript, depending on the target population. [14] Design the questionnaire in order that respondents must be able to complete it without the use of a graphic browser if they use a textbased to obtain information from the Web. [14] Not require users to make alterations to their browser’s preferences. [14] Do not use Java Script for online survey. [14]	Maintain the file’s imagines as small as possible. [10] Not use browser-specific HTML extensions. [14] Design the questionnaire in order that respondents must be able to complete it without the use of a graphic browser if they use a textbased to obtain information from the Web. [14] Not require users to make alterations to their browser’s preferences. [14] Remember that different phone platforms have different implementation environments. [14] Do not use Java Script for online survey. [10]