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 Lumbar Spine Fusion for Degenerative Disease, 1-3 Levels episode-based cost measure evaluates a clinician's risk-adjusted cost to Medicare for patients who undergo surgery for lumbar spine fusion during the performance period. The measure score is the clinician's riskadjusted 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.