ABSTRACT
This chapter aims to quantify the relationship between descriptive norms and intentions. It assesses the predictive validity of descriptive norms after theory of planned behavior (TPB) predictors have been taken into account, and examines age and type of health behavior as potential moderators of the relationship between descriptive norms and intentions. A regression analysis showed that TPB variables explained 39 percent of the variance in intentions–the identical proportion of variance obtained in C. J. Armitage and M. Conner's meta-analysis of the TPB. The predictive success of descriptive norms in the context of the TPB has considerable theoretical value. The findings from the current review satisfy one inclusion criterion and provide the best evidence to date to support the inclusion of descriptive norms as an additional predictor in the TPB. Younger samples and health-risk behaviors were both associated with stronger correlations between descriptive norms and intention.
