Improving quality of care in arthroplasty is of increasing importance to payors, hospitals, surgeons, and patients. Efforts to compel improvement have traditionally focused measurement and reporting of data describing structural factors, care processes (or 'quality measures'), and clinical outcomes. Reporting structural measures (eg, surgical case volume) has been used with varying degrees of success. Care process measures, exemplified by initiatives such as the Surgical Care Improvement Project measures, are chosen based on the strength of randomized trial evidence linking the process to improved outcomes. However, evidence linking improved performance on Surgical Care Improvement Project measures with improved outcomes is limited. Outcome measures in surgery are of increasing importance as an approach to compel care improvement with prominent examples represented by the National Surgical Quality Improvement Project. Although outcomes-focused approaches are often costly, when linked to active benchmarking and collaborative activities, they may improve care broadly. Moreover, implementation of computerized data systems collecting information formerly collected on paper only will facilitate benchmarking. In the end, care will only be improved if these data are used to define methods for innovating care systems that deliver better outcomes at lower or equivalent costs.