The ostensible goal of outcomes research is to demonstrate the effectiveness of total joint replacement as it relates to appropriate use of health care resources and quality of care. Modern outcomes assessment focuses on identifying reproducible and valid instruments that can be used to collect and analyze patient outcomes. Validation of the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) has had a major impact on obtaining meaningful outcomes data. Its use, as well as use of other outcomes instruments, is addressed in this article. The final frontier in outcomes research is the large-scale database. Early data from the Swedish National Total Hip Arthroplasty Registry is encouraging, but its ultimate usefulness is unknown. There are significant obstacles to development of such a system in the United States. At this time, the direction of outcomes research needs to be reassessed.