Fig. (1) Area under the ROC curve of several scales, with diseased to non-diseased ratio is 1:3 (a) or 1:1 (b) (adopted from Kourlaba G and Panagiotakos DB, 2009 (9)).Study 1: The sample size of each simulated data set was 1000 and each scale was constructed summing 10 components.Study 2: The sample size of each simulated data set was 100 and each scale was constructed summing 10 components.Study 3: The sample size of each simulated data set was 1000 and each scale was constructed summing 5 components.Study 4: The sample size of each simulated data set was 100 and each scale was constructed summing 5 components.