Risk Comprehension and Judgments of Statistical Evidentiary Appeals: When a Picture Is Not Worth a Thousand Words

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Too little theory and research has considered the effects of communicating statistics in various forms on comprehension, perceptions of evidence quality, or evaluations of message persuasiveness. In a considered extension of Subjective Message Construct Theory (Morley, 1987), we advance a rationale relating evidence form to the formation of impressions of evidence. We compare visual versus verbal representations of statistical evidence associated with multivariate relationships in a community-based field experiment (N = 206). Verbal forms were found to be better comprehended than visual forms and contributed to enhanced understanding when compared to an attention control condition. Comprehension was found to mediate the effect of statistical evidence form on perceptions of evidence quality, while comprehension and perceptions of evidence quality moderated judgments of message persuasiveness. In addition to the effects of evidence form on subjective impressions of statistical evidence, we advance perceiver characteristics as another realm in which persuaders may identify persistent patterns associated with comprehension and judgments of statistical evidence. Numeracy skills, race, and gender emerge as characteristics with merit in this regard. Nonsignificant findings associated with perceiver characteristics were found. Finally, we consider the results for evidence form and perceiver characteristics on comprehension and judgments of statistical evidence for their theoretic and pragmatic importance.