Abstract
Quality of care refers to the degree to which health services increase the likelihood of desired health outcomes. The evaluation of quality depends on the assessment of process, structure, and outcomes of medical care. Outcomes research focuses on the results of medical care and differs from traditional clinical research in two ways: 1) outcomes research uses nonrandomized research methodologies, and 2) it uses an expanded description of patient outcomes. The results of outcomes studies will be used to measure treatment effectiveness, assess quality of care, and measure provider performance.