Reviewed and summarized rigorous evaluations of psychosocial and educational interventions aimed at the primary prevention of alcohol misuse by young people aged up to 25 yrs, especially over the longer term (3 yrs or more). A comprehensive search was conducted of 22 databases and recursive checking was done of bibliographies for randomized and non-randomized controlled trials and interrupted time-series studies. 20 of the 56 studies selected for inclusion showed evidence of ineffectiveness. No firm conclusions about the effectiveness of prevention interventions in the short- and medium term were possible. Over the longer term, the Strengthening Families Programme (SFP) showed promise as an effective prevention intervention. The Number Needed to Treat (NNT) for the SFP over 4 yrs for three alcohol initiation behaviors (alcohol use, alcohol use without permission and first drunkenness) was 9 (for all 3 behaviors). One study also highlighted the potential value of culturally focused skills training over the longer-term. Conclusions include the ideas that (1) research into important outcome variables needs to be undertaken; (2) the methodology of evaluations needs to be improved; and (3) the SFP needs to be evaluated on a larger scale and in different settings. (PsycINFO Database Record (c) 2003 APA, all rights reserved)