Project Summary During this time of rapid evolution and uncertain future in the US healthcare system, it is critical that the US prepare a new generation of scientific leaders with the interdisciplinary training, flexible critical thinking skills and real-world grounding to provide the necessary leadership to make sound decisions for our future. The University of California, Berkeley (UC Berkeley) and University of California, San Francisco (UCSF), widely regarded as two of the top public universities in the world, both have long-standing health services research (HSR) training programs. UC Berkeley and UCSF propose a five-year renewal of the joint HSR T32 training program for four predoctoral and two postdoctoral trainees. The overall objective of the fellowship program is to harness collaboration, complementary skills, and training capacity of the two institutions to provide an outstanding training experience that emphasizes the application of interdisciplinary advances in social, behavioral, and data sciences to real world challenges of clinicians, healthcare delivery systems, and health policy makers. The predoctoral program provides rigorous training in research methods central to HSR, including data science, quasi-experimental methods, econometrics, and implementation science, as well as opportunities to partner with health care organizations and systems to conduct research that is responsive to their priorities. Predoctoral trainees are required to have previously completed coursework in epidemiology, economics, and statistics, and during our program they complete courses in research design, advanced statistics, health economics, public policy, and organization behavior. The four predoctoral traineeships are selected on an annual basis and each can be reappointed for an additional year, depending on coursework and research performance. The postdoctoral program, administered by the UCSF Philip R. Lee Institute for Health Policy Studies, is a two-year fellowship program that provides intensive experiential HSR training to doctorally-trained social and behavioral scientists, as well as doctoral-level health professionals with the equivalent of an MPH degree. Throughout their training, trainees participate in biweekly colloquia at UCSF and UC Berkeley to expose them to cutting edge research in progress by nationally and internationally recognized health services researchers.