Injunctive and Descriptive Normative Feedback for College Drinking Prevention: Is the Whole Greater Than the Sum of Its Parts?

Objective: Single-component personalized normative feedback (PNF) interventions and multicomponent personalized feedback interventions (PFI) have been shown to reduce alcohol consumption among college students. The present study compared the efficacy of PNF interventions targeting descriptive norms alone (descriptive PNF), injunctive norms alone (injunctive PNF), or their combination (combined PNF), against a multicomponent PFI and an attention control condition. Method: Undergraduates (N = 1,137) across two universities who reported a minimum of one past-month episode of heavy episodic drinking (i.e., 4+/5+ drinks on a single occasion for females/males) completed assessments at baseline and 3, 6, and 12 months postintervention. Results: Relative to the attention control, participants in each of the four intervention conditions showed greater reductions in perceived descriptive/injunctive norms, total drinks per week, and alcohol-related consequences. Peak estimated blood alcohol concentration was also reduced in the injunctive PNF, combined PNF, and multicomponent PFI conditions, with the latter two conditions showing an advantage for duration of effects. The multicomponent PFI condition also evidenced greater reductions than the injunctive PNF in descriptive norms at 3-month and injunctive norms at 6- and 12-month follow-ups. No other group comparisons on any outcome were significant. Conclusions: Each intervention has merit for use in college student harm reduction efforts. Single-component or combined PNF could be considered a potential starting point, as PNF is less burdensome than a multicomponent PFI when considering ease and length of delivery. Results can inform optimization of norms-based interventions and guide recommendations on efficacious components for reducing alcohol use and harms on college campuses. Public Health Significance Statement This study examined relative efficacy of four web-based interventions for college student drinking containing normative feedback, all of which showed evidence of efficacy compared to an attention control condition. The three personalized normative feedback interventions (focused individually on descriptive and injunctive norms and their combination) showed relatively comparable efficacy to a comprehensive multicomponent personalized feedback intervention (inclusive of both types of normative feedback and other elements) and may be easier to scale.