Black N, Eisma MC, Viechtbauer W, et al. - Researchers investigated the variability and effectiveness of interventions provided to comparator (control) groups in smoking cessation trials. Randomized controlled trials (RCTs) of behavioral interventions for smoking cessation, with or without stop-smoking medication were systematically reviewed with meta-analysis. The Cochrane Tobacco Addiction Group Specialized Register was inquired for RCTs with objective outcomes measured at ≥ 6 months. For these analyses, they identified 104 of 142 eligible comparator groups (n = 23,706) with complete data for inclusion. The analysis revealed considerable variation, in terms of content, in interventions delivered to comparator groups in smoking cessation randomized controlled trials. Stop-smoking medication and the number of behavior change techniques delivered were identified as strong predictors of cessation rates.