We included a 13-item shortened version (MC-C; Reynolds, 1982) of the original Marlowe-Crowne Social Desirability Scale (MC; Crowne & Marlowe, 1960) that assesses a person's tendency to present himself or herself in a socially desirable way. This short version has been found to discriminate criminal and non-criminal groups and been known to have acceptable test-retest reliability and internal consistency (Andrews & Meyer, 2003). We included this social desirability scale in the baseline assessment to control for potential demand characteristics among mandated students in reporting substance use. Example items are “I'm always willing to admit it when I make a mistake”, “I have never deliberately said something that hurt someone's feelings”, or “I have never been annoyed when people expressed ideas very different from my own.” Responses were coded 1 for True and 0 for False responses. The scale score was created by summing responses (α = .66 at baseline). High scores indicate higher levels of social desirability. Mandated students may be more motivated to underreport alcohol use levels than volunteer students. Previously we reported from a different sample that mandated
