The BioBridge Professional Development model was created to bring current and relevant science into the high school classroom. The purpose of this intervention was to connect teachers with relevant science and to create innovative, hands-on activities that engage students, with the goal of increasing student interest in STEM careers. To this end, the authors created and implemented a professional development model based on current scientific research at the University of California, San Diego (UCSD). Project research objectives were: (1) to determine whether the basic BioBridge Professional Development (PD) model is transportable across districts; (2) to determine if the model's fundamental template is adaptable across a range of science subject areas; (3) to determine if the model is seen as useful by teachers in terms of their training outcomes; and (4) to discover whether teacher-scientist teams can collaboratively adapt lab-based research into discovery-oriented learning activities suitable for instructional use in authentic high school classrooms. The proposed poster will share methods used to observe teachers' classroom implementation of the materials and pedagogy from the PD, with a particular focus on the ways that these data have been used to establish a fidelity of implementation score. A secondary purpose of the poster will be to describe district-level End of Course Exam data that have been analyzed in relation to FI scores to understand whether and how the fidelity metric relates to student outcomes. The program serves three school districts, including 38 high schools, from diverse ethnic and socio-economic populations in both urban and suburban locations. More than 300 teachers and 90,000 students have participated in the program over the course of three years. The results of the fidelity of implementation assessment indicate that the BioBridge program has not yet reached its goal of having 75% of teachers implement at fidelity. Changes have been made to more clearly define the fidelity of implementation measures and how that translates into the classroom implementations. The results of student test score analysis are encouraging, but it is clear that additional training and/or support must be provided to teachers in order to achieve broad student impact. The BioBridge team is currently exploring program modifications that will increase the success of Bachelor's-level teachers. One approach under consideration is offering differentiated training for Bachelor's and Master's-level teachers. Another possibility is to create communities of practice within schools that cluster Master's-level with Bachelor's-level teachers