Studying Variation in Program Success

Multilevel modeling techniques, although used extensively in numerous areas of social science research including demography, studies of school organization, and research on cognitive development, have been used surprisingly infrequently in multisite evaluation studies. The goal of this article is to illustrate several ways in which multilevel modeling techniques can help to broaden the kinds of questions that we are able to address in multisite evaluations. In particular, it is shown how these techniques provide a means of moving beyond estimating overall, average program effects to investigations of how differences in various aspects of implementation across sites relate to differences in program success.