Building Excellent Educators of Science Initiative (BEES) is a multi-year initiative that seeks to increase student exposure to culturally relevant and accessible science instruction by improving elementary school teachers' capacity to confidently deliver high quality, standard aligned science lessons to grades 2-6. To support BEES’s mission, PRE is working closely with BPS to conduct a 2 year, mixed-method formative evaluation of BEES to understand how the programs works and to determine if participation in BEES has an impact on science outcomes for students.