ArticlesArticles should deal with topics applicable to the broad field of program evaluation. Articles may focus on evaluation methods, theory, practice, or findings. In all cases, implications for practicing evaluators should be clearly identified. Examples of contributions include, but are not limited to, reviews of new developments in evaluation, descriptions of a current evaluation study, critical reviews of some area of evaluation practice, and presentations of important new techniques. Manuscripts should follow APA format for references and style. Length per se is not a criterion in evaluating submissions. However, manuscripts in excess of 35 double-spaced pages may be returned to the authors without review at the discretion of the editor.Abstract: The evaluation of an intervention delivered across multiple treatment sites presents a unique opportunity for evaluators to gauge the manner and degree to which the "impact" of treatment varies across implementation conditions and different target populations. However, the availability of implementation data for each treatment site, while presenting the opportunity for more sophisticated impact assessment, also presents an analytic challenge. In the following, multilevel growth models were applied to data describing students and classroom sites to demonstrate how the multilevel modeling framework can be used to analyze data obtained from a multisite program implementation. Results of the investigation indicated that increased adherence to the program model was not associated with more positive recipient outcomes. Further examination of the null finding indicated that the highest and lowest rates of literacy growth observed in the study were concentrated in several lowimplementing sites. Implications for multisite evaluation design and practice are discussed.