Understanding evaluations of home visitation programs

This journal issue comprises reports concerning program evaluations of key national home visitation models. No single evaluation can answer all the qu estions of interest about a program, nor is any evaluation perfect, which m eans that readers must carefully weigh the intended purpose of the evaluati on and the evaluation's strengths and weaknesses before deciding what concl usions can credibly be drawn from its results. This article begins with a discussion of the role of evaluation both in imp roving prog-rams and in determining program effects. The choices required t o craft a strong and methodologically rigorous evaluation are described: wh at outcomes to measure and how; what methods to use in designing the evalua tion and building a comparison group; how many participants to enroll; and how to devise a strong plan for data analysis involving subgroups of the en rolled families. The article then discusses additional factors policymakers and practitioner s should consider when interpreting the results of home visiting evaluation s: attrition, the policy and functional importance of the outcomes, and the likely generalizability of the results to other communities or other popul ations. The evaluations that appear in this journal issue are used as examples thro ughout the article, and the measures that were used in those evaluations ar e summarized. The evaluations included in this journal issue have both stre ngths and weaknesses but are probably among the better evaluation in the ho me visiting field.