The purpose of this article is to describe a new approach for conducting multi-site evaluations of professional development (PD). The approach extends a popular model of PD evaluation through the creation of individual project profiles that take into account the unique contextual variables of individual projects while providing an evaluation picture of the overall program. We provide illustrative evaluation results highlighting the importance of understanding project contexts. Through two case comparisons, we demonstrate how case-based context informed our interpretation of outcomes data. Finally, we discuss how our approach maps onto and extends a popular model for professional development evaluation.