A METAANALYSIS OF SMOKING PREVENTION PROGRAMS AFTER ADJUSTMENT FOR ERRORS IN THE UNIT OF ANALYSIS

This article presents the results of a meta-analysis designed to test the prevailing view that we largely understand why adolescents start t o smoke and how to delay it. This view has developed even though none of the major reviews of the last 12 years has adjusted for the importa nt methodological problems that all of those reviews identified as com mon in the published literature. School-based smoking prevention progr ams based on peer or social-type programs, published between 1974 and 1991, were included in this mete-analysis. Treatment characteristics w ere used to predict an effect size after adjustment for study design a nd population characteristics, and in particular, after a post hoc cor rection for errors int he original unit of analysis. The results sugge st that the average effect for peer or social-type programs is likely to be quite limited in magnitude, and that the reduction in smoking ma y be only 0.10 standard deviation units, or perhaps 5%. Even under opt imal conditions, the reduction in smoking may be only 0.50 to 0.75 sta ndard deviation units, or perhaps 20%-30%.