In setting priorities for funding and support, intervention programs demonstrated to be effective and efficient are preferred over programs that are well intentioned but untested by rigorous evaluation. An evidence-based approach is undeniably better than an approach based on faith or anecdotes, but the findings of existing evaluations are not sufficient by themselves as a basis for effective policy-making. Translating research into practice requires more than a review of existing studies. It requires knowledge of the research process and its limitations.