In addition to these and other efforts to raise public, patient, and provider awareness about disparities in care, carefully designed studies are necessary to identify the underlying determinants of disparities and the best strategies for eliminating them. Race/ethnicity is intertwined with many dimensions of the U.S. health care system, and the association between race/ethnicity and medical care, as concluded by the IOM, may reflect any number of factors, including patient, physician, and health system characteristics. Differences in patients’ awareness of symptoms and their preferences about care may contribute to these disparities, for example. The biases of physicians in the clinical assessment or referral process, combined with uneven application of practice guidelines, may be another factor. In addition, characteristics of the health system (such as lack of health insurance or inadequate supply of cardiologists in medically underserved areas) may impede the provision of cardiac care. Even for those with access to health care, lack of effective case coordination, exacerbated by antiquated information technology systems and perverse reimbursement policies, may undermine the provision of quality cardiac care. In actuality, the disparity most likely results from a combination of these factors.