Pictorial cigarette pack warnings: a meta-analysis of experimental studies

To inform international research and policy, we conducted a meta-analysis of the experimental literature on pictorial cigarette pack warnings. DATA SOURCES: We systematically searched 7 computerised databases in April 2013 using several search terms. We also searched reference lists of relevant articles. STUDY SELECTION: We included studies that used an experimental protocol to test cigarette pack warnings and reported data on both pictorial and text-only conditions. 37 studies with data on 48 independent samples (N=33,613) met criteria. DATA EXTRACTION AND SYNTHESIS: Two independent coders coded all study characteristics. Effect sizes were computed from data extracted from study reports and were combined using random effects meta-analytic procedures.

Pictorial warnings were more effective than text-only warnings for 12 of 17 effectiveness outcomes (all p