To best influence policymakers, researchers need to provide information and measures of effects that reflect the nature of policy decisions. Specifically, policymakers are often interested in factors associated with changes in the number of cases or rate of disorders in a community. Regression/analysis of variance (ANOVA) models, which focus on the prediction of means, slopes, and variances, do not directly address such questions. In contrast, epidemiological statistics, which focus on differences in proportions of cases, do provide such information. Three epidemiological measures of effect (the risk-ratio, the odds-ratio, and the population attributable fraction) are reviewed; their value as tools for informing public policy is discussed; and examples are provided illustrating their use. Researchers are encouraged to consider adopting an epidemiological perspective as part of their work