This paper presents data from a systematic review and meta-analysis of 29 published studies of therapeutic community effectiveness using controls, including 8 randomised control trials. Meta-regressions suggest that the two types of therapeutic community, democratic and concept-based, and the age of the study, are the key sources of heterogeneity in the collection of studies analysed. Otherwise, heterogeneity is low and the meta-analysis confirms the effectiveness of therapeutic community treatment with overall summary log odds ratio for the 29 studies of 0.512 (95% ci -0.598 to -0.426).