Sixteen studies were identified: 3 randomised controlled trials (RCTs; n=213), 7 single-group studies with post-test data (n at least 466 at baseline) and 6 single-group studies with follow-up data (n=662 at baseline). The authors also stated that two dissertations were not included as the number of other studies was so low.
Single-group, post-test data only.
Most of the studies were group programmes lasting for a median of 6 hours. Half of them included additional sessions with counsellors. The evaluation of the interventions in the studies was generally minimal, although 2 studies reported that students stated that they had reduced their alcohol consumption, a third study reported no change in consumption rates, and three reported low rates of recidivism. The length of follow-up was often unclear and sample sizes were usually small (less than 45 participants).
Single-group with follow-up data.
Most of the studies used group programmes and typically lasted for 3 hours; the follow-up periods tended to be short (2 weeks to 3 months). Overall, the within-group effect sizes ranged from 0.09 to 1.59, although most were in the moderate range of 0.2 to 0.8. Two studies reported that consumption of alcohol was significantly reduced, but neither used validated measures of alcohol consumption. No other study suggested any statistically significant results in any of the outcomes.
RCTs.
Overall, the between-group effect sizes of the 3 trials were generally small to moderate for all outcomes reported. The exception was one study that found a large, statistically significant effect size, suggesting that the control group had a greater alcohol knowledge than the intervention group. However, this study was only based on 25 participants.