PROJECT SUMMARY/ABSTRACT The University of Chicago (UC) is requesting continued support from the Agency for Healthcare Research and Quality (AHRQ) for the National Research Service Award (NRSA) program entitled the University of Chicago And Northwestern University Predoctoral Health Services Research Program (hereafter, UCANU Predoctoral HSR Program). The program will provide two to three years of support to outstanding candidates from predoctoral programs from both UC and NU, leading to careers in health services research. UC has been an ideal site in which to provide broad-based training in health services due to the extraordinary strength of its faculty in health services research and in the social science, biomedical, and statistical disciplines upon which HSR draws. The high caliber of students at UC has been a notable strength of the ongoing and proposed programs. Likewise, Northwestern University's (NU) Health Sciences Integrated PhD Program (HSIP) has successfully recruited and trained students in its health services and outcomes research track, drawing students from a broad array of health professional fields and research disciplines. This joint partnership of UC and NU, which began in 2013, has proven to be highly successful during these past 5 years by offering a unique opportunity for the UCANU Predoctoral HSR Program trainees to leverage the extensive resources, expert faculty, and dedicated mentors across both institutions. The support of AHRQ and the availability of NRSA funding for trainees in the past nineteen years have helped each institution to expand upon the existing, successful research and training programs in HSR by making each site more appealing to students with such interests and attracting even more of each institution's talented and promising students into the field. In this application, we propose to continue to advance our training by enhancing our didactic and experiential offerings to better prepare trainees to function as key members of learning health care systems, leveraging opportunities for the practical application of HSR at both UC and NU while preparing trainees to apply their HSR training throughout the health care system.