Systematic reviews on tobacco control from Cochrane and the Community Guide: Different methods, similar findings

Objectives: To compare the methods and findings of systematic reviews (SRs) on common tobacco control interventions from two organizations: the Cochrane Collaboration ("Cochrane") and the US Task Force for Community Preventive Services ("the Guide"). Study Design and Setting: Literature review. We retrieved all reviews pertaining to tobacco control produced by the Cochrane and the Guide. We identified seven common topics and compared methods and findings of the retrieved reviews. Results: There was considerable variability in the designs of included studies and methods of data synthesis. On average, Cochrane identified more studies than did the Guide (Mean 43.7 vs. 19.0), with only limited overlap between sets of included studies. Most Cochrane reviews (71.4%) were synthesized narratively, whereas most Guide reviews (85.7%) were synthesized using a median of effect size. Despite these differences, findings of the reviews yielded substantial agreement. Conclusion: Cochrane and the Guide conduct SRs on similar tobacco control-related topics differently. The SRs of the two organizations include overlapping, but nonidentical sets, of studies. Still, they usually reach similar conclusions. Identification of all pertinent original studies seems to be a weak point in the SR process. Policy makers should use reviews from both organizations in formulating tobacco control policy.