Assessing fidelity of implementation is becoming increasingly important in education research, in particular as a tool for understanding variations in treatment effectiveness. Fidelity of implementation is defined as "the determination of how well an intervention is implemented in comparison with the original program design during an efficacy…

Recent studies on professional development programs indicate these programs, when sustained, have a positive impact on student achievement; however, many of these studies have failed to use longitudinal data. The purpose of this study is to understand how one particular instructional practice (STEM PBL) used consistently influences student…