Katherine E. Stiles is a Senior Program Associate in the STEM Program at WestEd. Katherine is Co-Director of WestEd's National Academy for Science and Mathematics Education Leadership, providing professional development and support for education leaders nationwide. The foci of the Leadership Academy-effective leadership, educational change, professional development and communities of learners, facilitation, and using data and evidence to achieve results-are reflected in the book, (2013). She designs and leads science and mathematics education program evaluation projects at the school, district, state, and national level, focusing on assessing the quality of professional development, and the relationship between teachers' conceptual learning, changes in practice, and student learning. Katherine works with schools and districts to enhance student learning through the development of collaborative inquiry into data among staff as part of her work on the Using Data Project and as co-author of (2008). She was co-director of an NSF-funded project, Building Systems for Quality Teaching and Learning in Science, that resulted in the publication of professional development materials and a simulation board game on science education. The project extended the work of the seminal book on professional development that she co-authored, (2010). Prior to joining WestEd in 1995, Katherine worked at the National Science Resources Center in Washington, D.C., as a science curriculum developer and authored four curriculum units for the program.