The data collection requirements for ASC-21: Risk-Standardized Patient-Reported Outcome-Based Performance Measure Following Elective Primary Total Hip Arthroplasty and/or Total Knee Arthroplasty in the ASC Setting are as voluminous as the title of the measure itself. With voluntary data collection and reporting underway, and mandatory preoperative data collection beginning the fourth quarter of 2027, now is the time to learn more about this measure in the Centers for Medicare & Medicaid Services’ ASC Quality Reporting Program.