Alcoholism treatment outcome studies, 1980-1992: methodological characteristics and quality.

We examine the methodological characteristics and provision of study information in 339 alcoholism treatment outcome studies reported between 1980 and 1992. We consider factors in four methodological domains: sampling and description of patients, specification of treatments, outcome variable assessment and follow-up, and treatment effect estimates; we also consider the methodological quality of the studies. Although methodological quality has improved over time, there remains room for improvement. Of special concern is the low statistical power of many studies. Multiple treatment group studies had an average .54 probability of detecting a treatment effect of medium size.