Fig. 3From: Retention in opioid agonist treatment: a rapid review and meta-analysis comparing observational studies and randomized controlled trialsBoxplots of mean retention rate for randomized controlled trials (RCTs), 4–6 months of follow-up. Retention rates are for buprenorphine and methadone, where the retention rate was measured as the number of patients who completed the study. All studies had follow-up rates between 4 and 6 monthsBack to article page