The goal of CS4NorthCal is to scale up an effective, evidence-based model for preparation, PD, and ongoing support of high school CS teachers. CS4NorthCal will prepare and support high school teachers committed to CS education excellence throughout Northern California. This project will increase rigorous and engaging CS course offerings to all high school students. The retention of students in high school CS courses will increase, and these students will gain in-demand skills that allow them to enter the CS workforce. The strategies identified and tested in this project for improving teacher preparation and support will be of broad interest, as school districts throughout the country are facing, or will face, the same problems, as they ramp up their own CS offerings. Over the course of this project, the RPP will serve 200 teachers and support 25,000+ high school students. San Francisco State University, WestEd, and 20+ school districts will collaborate and launch CS4NorthCal to address the critical national need to broaden the availability of high-quality computer science (CS) education to all American students by creating a scalable and effective model for teacher preparation. The project has three main activities: (1) scaling a certification program for CS teacher preparation and professional development to increase the number of authorized high school CS teachers; (2) expanding Professional Learning Communities (PLCs) for newly certified high school CS teachers to prov