This paper describes the application of Guskey' five-level model for evaluating professional development to a pd program for elementary science teachers in Northern Arizona. The model is used as a reflective tool to to examine successes and challenges to evaluating the Teaching Science from Inquiry to Understanding program. We describe data collection activities at each level and how lessons learned in year one informed revisions to evaluation activities for year two. We examine overall lessons learned from evaluation of the program. #2010Conference #Prek-12EducationalEvaluation