Psychometric evaluation of the Situational Confidence Questionnaire in adolescents: fitting a graded item response model.

Self-efficacy theory has been extensively applied to alcoholism treatment, theories of relapse, and relapse prevention. Most empirical studies of perceived self-efficacy to resist heavy drinking have used the Situational Confidence Questionnaire (SCQ). Among adults, this instrument has been shown to be psychometrically sound. Little is known, however, about the psychometric properties of the SCQ in the adolescent population. We administered the SCQ to a sample of 662 adolescents to evaluate its psychometric properties. Each of the eight subscales was found to be unidimensional. Invariance of the item parameters across different groups was also examined. The reliability coefficients, based on item response theory (marginal reliability) and classical measurement theory (Cronbach alpha), were found to be high. These results demonstrate that the SCQ is appropriate for use among adolescents.