The evaluation of injury prevention interventions is important before the widespread dissemination of these interventions. One level of evaluation is at the population level, to determine the effect of the intervention on the incidence of injury. The size and nature of the study population depend on the study design, the nature of the intervention, and the outcome measures of interest. Possible designs are randomized controlled trials; nonrandomized controlled trials; and observational studies, including cohort, case-control, and ecologic designs. These strategies have been successfully applied to evaluate a wide variety of interventions for intentional and unintentional injury prevention, the results of which have been used to guide public policy. These same strategies can be successfully used to evaluate methods for the prevention of injury due to child abuse.