title: Pictorial cigarette pack warnings: a meta-analysis of experimental studies.
abstract: OBJECTIVE
  To inform international research and policy, we conducted a meta-analysis of the experimental literature on pictorial cigarette pack warnings.
  
  
  METHODS
  We systematically searched 7 computerised databases in April 2013 using several search terms. We also searched reference lists of relevant articles.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  Pictorial warnings were more effective than text-only warnings for 12 of 17 effectiveness outcomes (all p<0.05). Relative to text-only warnings, pictorial warnings (1) attracted and held attention better; (2) garnered stronger cognitive and emotional reactions; (3) elicited more negative pack attitudes and negative smoking attitudes and (4) more effectively increased intentions to not start smoking and to quit smoking. Participants also perceived pictorial warnings as being more effective than text-only warnings across all 8 perceived effectiveness outcomes.
  
  
  CONCLUSIONS
  The evidence from this international body of literature supports pictorial cigarette pack warnings as more effective than text-only warnings. Gaps in the literature include a lack of assessment of smoking behaviour and a dearth of theory-based research on how warnings exert their effects.
authors.affiliation: School of Journalism and Mass Communication, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Seth M
authors.initials: SM
authors.lastname: Noar
authors.affiliation: Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Marissa G
authors.initials: MG
authors.lastname: Hall
authors.affiliation: School of Journalism and Mass Communication, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Diane B
authors.initials: DB
authors.lastname: Francis
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Kurt M
authors.initials: KM
authors.lastname: Ribisl
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Pepper
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Department of Health Behavior, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Noel T
authors.initials: NT
authors.lastname: Brewer
mesh_terms: D001288:Attention; D003071:Cognition; D015438:Health Behavior; D006266:Health Education / Q000379:methods*; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D009042:Motivation; D010781:Photography; D011356:Product Labeling; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000523:psychology; D016540:Smoking Cessation / Q000523:psychology*; D000074606:Smoking Prevention; D062789:Tobacco Products / Q000009:adverse effects*; D014796:Visual Perception
keywords: Global health; Packaging and Labelling; Public policy