Background Drinking is influenced by youth (mis) perceptions of how their peers drink. If misperceptions can be corrected, young people may drink less. Objectives To determine whether social norms interventions reduce alcohol-related negative consequences, alcoholmisuse or alcohol consumption when compared with a control (ranging from assessment only/no intervention to other educational or psychosocial interventions) among university and college students. Search methods The following electronic databases were searched up to May 2014: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (only to March 2008). Reference lists of included studies and review articles were manually searched. Selection criteria Randomised controlled trials or cluster-randomised controlled trials that compared a social normative intervention versus no intervention, alcohol education leaflet or other 'non-normative feedback' alcohol intervention and reported on alcohol consumption or alcoholrelated problems in university or college students. Data collection and analysis We used standard methodological procedures as expected by The Cochrane Collaboration. Each outcome was analysed by mode of delivery: mailed normative feedback (MF); Web/computer normative feedback (WF); individual face-to-face normative feedback (IFF); group face-to-face normative feedback (GFF); and normative marketing campaign (MC). Main results A total of 66 studies (43,125 participants) were included in the review, and 59 studies (40,951 participants) in the meta-analyses. Outcomes at 4+ months post intervention were of particular interest to assess when effects were sustained beyond the immediate short term. We have reported pooled effects across delivery modes only for those analyses for which heterogeneity across delivery modes is not substantial (I-2 < 50%). Alcohol-related problems at 4+ months: IFF standardised mean difference (SMD) -0.16, 95% confidence interval (CI) -0.31 to 0.01 (participants = 1065; studies = 7; moderate quality of evidence), equivalent to a decrease of 1.5 points in the 69-point alcohol problems scale score. No effects were found for WF or MF. Binge drinking at 4+ months: results pooled across delivery modes: SMD -0.06, 95% CI -0.11 to -0.02 (participants = 11,292; studies = 16; moderate quality of evidence), equivalent to 2.7% fewer binge drinkers if 30-day prevalence is 43.9%. Drinking quantity at 4+ months: results pooled across delivery modes: SMD -0.08, 95% CI -0.12 to -0.05 (participants = 20,696; studies = 33; moderate quality of evidence), equivalent to a reduction of 0.9 drinks consumed each week, from a baseline of 13.7 drinks per week. Drinking frequency at 4+ months: WF SMD -0.12, 95% CI -0.18 to -0.05 (participants = 9456; studies = 9; moderate quality of evidence), equivalent to a decrease of 0.19 drinking days/wk, from a baseline of 2.74 days/wk; IFF SMD -0.21, 95% CI -0.31 to -0.10 (participants = 1464; studies = 8; moderate quality of evidence), equivalent to a decrease of 0.32 drinking days/wk, from a baseline of 2.74 days/wk. No effects were found for GFF or MC. Estimated blood alcohol concentration (BAC) at 4+ months: peak BAC results pooled across delivery modes: SMD -0.08, 95% CI -0.17 to 0.00 (participants = 7198; studies = 13; low quality of evidence), equivalent to a reduction in peak PAC from an average of 0.144% to 0.135%. No effects were found for typical BAC with IFF. Authors' conclusions The results of this review indicate that no substantive meaningful benefits are associated with social norms interventions for prevention of alcohol misuse among college/university students. Although some significant effects were found, we interpret the effect sizes as too small, given the measurement scales used in the studies included in this review, to be of relevance for policy or practice. Moreover, the statistically significant effects are not consistent for all misuse measures, heterogeneity was a problem in some analyses and bias cannot be discounted as a potential cause of these findings.
