Members of the MSU AACR team (Mark Urban-Lurain, PI; John Merrill, co-PI and Kevin Haudek, co-PI) and collaborators from BSCS in Colorado have received an award totaling $750,000 from the National Science Foundation to extend the AACR work into reseach on K-12 science teachers pedagogical content knowledge. The project, Collaborative Research: PCK*Lex – Applying Computerized Lexical Analysis to Develop a Cost-Effective Measure of Science Teacher Pedagogical Content Knowledge, begins October 1, 2014 and runs for three years. The project will apply computerized lexical analysis techniques to develop an efficient, valid and reliable measure of science teacher pedagogical content knowledge (PCK) - the type of teacher knowledge that bridges content knowledge and how to effectively teach the content in classrooms. PCK is a critical conceptual tool for distinguishing effective from ineffective teaching, but difficulty measuring it has resulted in minimal application of the concept to enhance actual teaching practice. This project will transform an instrument used in multiple NSF STEM projects, but which is limited by being time and resource intensive to score. Application of recent developments in lexical analysis will allow measurement of PCK to be taken to scale with rapid feedback, and will be a vital resource for STEM researchers, evaluators, PD providers, teacher educators, and teachers themselves. This collaborative research project brings together two teams with unique yet complementary expertise. BSCS researchers have experience measuring PCK in multiple federal projects, and recently led an international summit on STEM PCK. The Michigan State University Automated Analysis of Constructed Response research group is working across STEM disciplines to refine approaches to using lexical analysis for formative educational purposes. Broader impacts of this project include developing a measure that will be invaluable to multiple stakeholders in evaluating and enhancing the understandings and abilities of K-12 science teachers. Enhancing the capacity of K-12 teachers will help increase the numbers of underrepresented students who pursue STEM careers, as well as expand the STEM workforce and increase general scientific literacy.