Ivan I. Lapuka Department of Marketing College of Business Administration

1. A Methodological EvaluationDo Product Warnings Increase Safe Behavior? A Meta AnalysisEli P. Cox III, Michael S. Wogalter, Sara L. Stokes, and Elizabeth J. Tipton Murff Ivan I. Lapuka Department of Marketing College of Business Administration University of South Florida

2. Research Domain • Journal of Public Policy & Marketing. • The authors focused on product warnings. • The research domain of this study is essentially two-faceted, as it interconnects the fields of (a) public policy and (b) consumer behavior.

3. Central Research Questions • Are product warnings an effective communication medium in the production of safe behavior of product users? • What factors are most influential in producing an effective warning? • The relationship between one explanatory (i.e., the presence of a product warning) and one response (i.e., warning compliance) variable.

4. Method/Technique • The first meta-analysis of the existing empirical research base centered on the relationship between the presence of product warnings and the safe behavior of product users. • The authors selected the research finding that has been investigated in primary research in various contexts and used meta-analysis to help them describe the overall strength of the effect and under what circumstances it is stronger and weaker.

5. Method/Literature Search &Study Acquisition • Only empirical studies that compared conditions with and without product warnings and used warning compliance as a criterion were included in the analysis. • Electronic databases and bibliographies. • Citations of relevant publications. • Contacted researchers. • Identified and obtained relevant unpublished theses and dissertations. • 14 studies reporting 15 experiments were included. • Not addressed: foreign studies, studies published in journals not indexed in one of the major electronic databases, citation bias, & multiple publications bias.

6. Method/Coding • Experimental conditions were the unit of analysis. • 15 experiments with 24 control conditions and 79 experimental conditions were analyzed; the combined sample size was 3229. • Two of the authors coded the studies. • Authors. • Number and description of participants. • Products. • Associated hazards. • Manifestations of safe behaviors. • Experimental conditions. • Independent variables. • Number of the treatment levels for each IV examined in a study that produced compliance rates greater than the control condition. • Reliability not calculated/reported.

7. Analysis/Effect Size Estimation • A random-effects model was used to account for the differing sample sizes among the experimental conditions. • The effect size for each experimental condition was estimated using Hedges & Olkin’s bias-corrected estimator. • The hypothesis that the effect-size variance component is 0 was tested by calculating the test statistic Q. • The mean of the distribution of warning effect sizes was estimated by a weighted average of the estimates of the individual observation effect sizes.

8. Analysis/Moderating Variables Examination • Weighted regression was used to: • estimate the impact of study artifacts (e.g., the sample sizes of the studies) contributing to the variation in warning study results; • assess the possible impact of using student subjects on marginal compliance rates.

9. Analysis/Bias Examination • The assumption of interdependence of observations was evaluated through a simulation. • Publication bias was examined by estimating the number of studies with negative results required to undermine the conclusion that warnings are generally effective in increasing safe behavior.

10. Results • The hypothesis that the effect-size variance component is 0 was rejected (a statistically significant Q of 210.68). • 29% of the variation in the observed effect sizes was due to variation in effect sizes themselves, whereas the remaining 71% of the variation was due to sampling error. • Warnings increased safe behavior in general in the studies examined (the estimated mean of the distribution of warning effect sizes & its variance were .311and .002, respectively; 0 was outside of the range of the 95%CI). • The examined study artifacts did not impact warning compliance in any meaningful way. • Warning compliance rates were found to be higher among studies using students as subjects. • The lack of independence among observations caused only a small overestimation of the mean compliance rate. • It was unlikely that there was a significant number of unpublished studies with negative results to undermine the conclusion that the presence of warnings generally increases safe behavior.

11. Overall Evaluation • Internal Validity • The internal validity of the primary research studies was not examined. • The sample of experimental conditions consisted of 79 cases; thus, power was adequate. • The authors did not report if there were any relationships between the examined moderators. • The authors did not report reliability. • External Validity • It is impossible to make a conclusion whether the authors conducted a truly exhaustive literature search. • Theoretical Contribution • The analysis provides a sufficient theoretical interpretation and integration. • The study greatly aids the literature by providing a retrospective summary of what can be found in the existing literature. • The authors gave suggestions with respect to areas within the literature that still need development.