Table 1: Items in the crosswise model questionnaire.

Items	Question Pairs	Answers
1	- Please recall the cell phone number of one of your friends or acquaintances. Is the last digit,1,2 or 3 ? - Have you ever used drugs?	A- if the answer to two sensitive and insensitive questions was “yes “or” No” B- “yes” to one of them and “no” to another one
2	- Please think about one of your female friends or acquaintances. Is her name Fateme, Zahra, or Maryam (either singularly or in combination with other names)? - Have you ever drunk alcohol?”	A- if the answer to two sensitive and insensitive questions was “yes”or” No” B- “yes” to one of them and “no” to another one
3	- Please recall the number of your father’s (or one of your acquaintances’) house. Is the right digit 2, 4, or 6? - Have you ever smoked cigarettes?	A- if the answer to two sensitive and insensitive questions was “yes”or” No” B- “yes” to one of them and “no” to another one