The overarching purpose behind this evaluation was to gauge the impact of AP® professional development (PD) on AP student outcomes in a state with a significant rate of PD implementation. The evaluation attempted to predict the level of student AP performance by the number of AP professional development events attended by teachers in that school in the prior year, while controlling for some socioeconomic status (SES), teacher, and school effects. This brief report describes the study data and methodology as well as the findings and conclusions.