Katherine E. Stiles, Senior Program Associate, STEM Program at WestEd, leads projects focused on professional development, science and mathematics education leadership development, teacher leadership, and program evaluation. Ms. Stiles is Co-Director of WestEd's National Academy for Science and Mathematics Education Leadership, providing professional development and support for education leaders nationwide. As a result of the Academy, she has provided support to numerous science and mathematics education leaders through diverse replication models in California, Illinois, Nevada, Puerto Rico, and Texas and in collaboration with organizations such as CSSS, NSELA, NSRC, and the University of Wisconsin–Madison SCALE initiative. She is co-director of an NSF-funded project, Building Systems for Quality Teaching and Learning in Science, creating science education professional development materials and a simulation board game on developing professional learning communities in school contexts. She is leading science and mathematics program evaluation projects in California focused on assessing the quality of professional development and the relationship between teacher learning and changes in practice. Ms. Stiles works with schools and school districts to enhance student learning through the development of collaborative inquiry into data among staff as part of her development work on the Using Data Project. Prior to joining WestEd in 1995, Ms. Stiles worked at the National Science Resources Center in Washington, D.C., as a science curriculum developer and authored curriculum units for the Science and Technology for Children program.