A comparison of three social-psychological models of attitude and behavioral plan: prediction of contraceptive behavior.

We compared the predictive validities of three prominent models of attitudes and behavioral decisions: Rosenberg's instrumentality-value model, Fishbein's belief-evaluation model, and Beach's adaptation of subjective expected utility theory. Seventy female undergraduates rated each of the models' components and reported their attitudes and behavioral plans toward using three different methods of contraception. With the traditional across-subjects prediction procedure, the Rosenberg model generally accounted for 5-25% less variance in subjects' attitudes and behavioral plans than the Fishbein an Beach models, which were not different. With a within-subject prediction procedure, the Rosenberg model was again the least accurate, and the Fishbein and Beach models had similar predictive accuracy. As hypothesized, within-subject predictions were more accurate than across-subjects predictions. The relatively poor performance of the Rosenberg model was attributable to the instrumentality component. In addition, we found that the Beach model could be simplified with no appreciable loss in predictive accuracy. Finally, a subject's personal normative beliefs emerged as a strong independent predictor of behavioral plan.