Review question: We reviewed evidence on the effects of social norms interventions (information to correct misperceptions about levels of consumption in peer groups) for alcohol misuse (alcohol-related problems, binge drinking, quantity and frequency of consumption and estimated blood alcohol concentrations). We found 66 studies.
Background: Damaging use of alcohol results in about 2.5 million deaths each year worldwide. About 320,000 of these deaths are reported in young people between the ages of 15 and 29 years, and they mainly result from car accidents, homicides (murders), suicides and drownings.
We wanted to find out whether social norms information had an effect on alcohol misuse in university or college students, among whom drinking rates and problems are often greater than in young people of similar age who are not at university or college. If those involved with tackling alcohol misuse in young people are to apply social norms approaches, clear evidence of effectiveness is required. This review updates a previous review published in 2009.
Search date: The evidence is current to May 2014.
Study characteristics: 66 studies were included in this review, with 43,125 students overall. We were interested mainly in studies with a follow-up period of four or more months to assess whether any effects were sustained beyond the immediate short term. The last follow-up period in these studies ranged from immediate post intervention to four years.
In 39 of the trials, the social norms intervention was targeted at higher-risk students (i.e. students who screened positive on a risky drinking test, or who were mandated to receive the intervention because of their behaviour and college rules). One trial involved only low-risk students, and the others (26 trials) included all students, regardless of alcohol use behaviour.
A total of 52 studies were conducted in the USA, and 14 studies were completed in other countries, including Australia, Brazil, New Zealand, Sweden and the United Kingdom.
Delivery of social norms information varied from study to study and included mailed feedback, web/computer feedback, individual face-to-face feedback, group face-to-face feedback and general social norms marketing campaigns across college campuses. In our analyses, we considered results separately for each mode of delivery if statistical evidence suggested that effects varied across different delivery modes.
We identified seven outcome measures that were covered by the trials in this review: (1) alcohol-related problems; (2) binge drinking; (3) quantity of drinking (e.g. drinks per week or per month); (4) frequency of drinking (e.g. number of drinking days in the typical week or month); (5 and 6) estimated peak and typical blood alcohol concentration (BAC), calculated using a formula that took account of consumption, gender and weight; and (7) drinking norms, reporting the perceived number of drinks consumed per occasion by a typical student.
At four or more months of follow-up, small effects were found for web feedback and individual face-to-face feedback on the outcomes of alcohol-related problems, binge drinking quantity of alcohol consumed, frequency of alcohol consumed and peak BAC.
No effects were found for mailed feedback on the outcomes of alcohol-related problems and group face-to-face feedback; or for marketing campaigns, on frequency of alcohol consumed and typical BAC.
No studies reported harms related to social norms information.
Our reading of these results is that, although we found some significant effects of social norms information among college/university students, the strength of the effects is small and therefore this information is unlikely to provide any advantage in practice.
Overall, only low or moderate quality of evidence was noted for the effects reported in this review. The quality of studies included in the review was variable. How students were allocated to study groups by chance was not reported adequately in many studies; only a few studies clearly reported how they disguised to which group students were allocated, and loss of students at follow-up was an issue in many studies. These problems with study quality could result in estimates of social norms effects that are too high, so we cannot rule out the chance that the effects observed in this review may be overstated. The evidence is current to May 2014.
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.
Drinking is influenced by youth (mis)perceptions of how their peers drink. If misperceptions can be corrected, young people may drink less.
To determine whether social norms interventions reduce alcohol-related negative consequences, alcohol misuse 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.
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.
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 alcohol-related problems in university or college students.
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).
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 (I2 < 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.