Background The Center for Outcomes Research (COR) serves as the scientific coordinating center for a growing number of national and international outcomes registries. COR’s responsibilities include maintaining patient and physician confidentiality, design of data collection instruments, data management and publication development. COR is based at the University of Massachusetts Medical School (UMMS) in Worcester, Massachusetts, part of the 5-campus UMass System. The medical school has 400 students and a full time faculty of approximately 600. A thriving center for research and clinical programs, UMass Medical School received over $100 million in research grants in 2001. Established in 1994, COR is an outgrowth of the Worcester Deep Vein Thrombosis Study, a five-year NIH-supported program, which demonstrated that physicians are more likely to improve their patient management practices if they are provided with valid data on their own practices and outcomes along with regional and national benchmarks. Fred Anderson, PhD, principal investigator of the Worcester DVT Study, and Research Professor of Surgery, turned the lessons of this study into the foundation for the Center for Outcomes Research. Currently, COR has a full time staff of 20 experienced scientists, clinical fellows, statisticians, information system specialists, research associates, and support staff. The COR team is proud to apply outcomes research methods to research and educational projects that contribute to improved patient care.