Comparative utility of a single-item versus multiple-item measure of self-efficacy in predicting relapse among young adults.

Single-item measures of psychological experiences are often viewed as psychometrically suspect. The purpose of this study was to evaluate the validity and utility of a single-item measure of self-efficacy in a clinical sample of treatment-seeking young adults. Inpatient young adults (N = 303, age = 18-24, 26% female) were assessed at intake to residential treatment, end of treatment, and at 1, 3, and 6 months following discharge. The single-item measure of self-efficacy consistently correlated positively with a well-established 20-item measure of self-efficacy and negatively with temptation scores from the same scale, demonstrating convergent and discriminant validity. It also consistently predicted relapse to substance use at 1-, 3-, and 6-month assessments postdischarge, even after controlling for other predictors of relapse (e.g., controlled environment), whereas global or subscale scores of the 20-item scale did not. Based on these findings, we encourage the use of this single-item measure of self-efficacy in research and clinical practice.