Effects of Communicating Prevalence Information about Two Common Health Conditions.

Obesity and diabetes are widespread health conditions with rising prevalence rates in the United States. News stories and health campaign messages frequently feature prevalence rates of obesity and diabetes, at times under the expectation that such messages will increase readers' disease awareness, health behaviors, and policy support. At the same time, American adults overestimate the prevalence of obesity and diabetes in the absence of prevalence information, raising important questions about the implications of communicating accurate prevalence information that may be lower than baseline estimates. The current study examines the effects of communicating information about the prevalence of obesity and diabetes, varying the format of this information (using qualitative terms, raw frequencies, or percentages). Results from two pre-registered, web-based randomized experiments suggest that only prevalence statistics in percentage formats shift readers' prevalence estimates, though in some percentage formats these estimates were lower than observed in a no-message control group. Prevalence estimates, in turn, were positively associated with perceived social causes of obesity/diabetes, intensions for healthy behaviors, and support for policy-level solutions. These findings offer guidance for health communication campaigns that seek to increase healthy behavior and support for policies to address health conditions.