Development and evaluation of the Marijuana Reduction Strategies Self-Efficacy Scale.

To evaluate several psychometric properties of a questionnaire designed to assess college students’self-efficacy to employ 21 cognitive–behavioral strategies intended to reduce the amount and/orfrequency with which they consume marijuana, we recruited 273 marijuana-using students to ratetheir confidence that they could employ each of the strategies. Examination of frequency counts foreach item, principal components analysis, internal consistency reliability, and mean interitemcorrelation supported retaining all 21 items in a single scale. In support of criterion validity,marijuana use-reduction self-efficacy scores were significantly positively correlated with cross-situational confidence to abstain from marijuana, and significantly negatively correlated withquantity and frequency of marijuana use and marijuana-related problems. In addition, compared withrespondents whose use of marijuana either increased or remained stable, self-efficacy was signifi-cantly higher among those who had decreased their use of marijuana over the past year. Thisrelatively short and easily administered questionnaire could be used to identify college students whohave low self-efficacy to employ specific marijuana reduction strategies and as an outcome measureto evaluate educational and skill-training interventions.