Episode-based cost measures represent the cost to Medicare for the items and services provided to a patient during an episode of care ("episode"). In all supplemental documentation, "cost" generally means the standardized Medicare allowed amount, and claims data from Medicare Parts A and B are used to construct the episode-based cost measures. The Elective Primary Hip Arthroplasty episode-based cost measure evaluates a clinician's riskadjusted cost to Medicare for patients who receive an elective primary hip arthroplasty during the performance period. The measure score is the clinician's risk-adjusted cost for the episode group averaged across all episodes attributed to the clinician. This procedural measure includes costs of services that are clinically related to the attributed clinician's role in managing care during each episode from 30 days prior to the clinical event that opens, or "triggers," the episode through 90 days after the trigger.