In a competitive marketplace, provider groups want better information on how they perform relative to their competition. This may be providers like them (e.g., other group practices) or other entities (e.g., academic medical centers or public hospitals). Purchasers also want to compare performance of plans on various measures of financial, quality, or operational performance, as reflected in the development of HEDIS 3.0 and other report-card measures. A variety of stakeholders want to understand how managed care entities perform relative to their theoretical potential to encourage coordination of care, preventative care, clinical integration, and system efficiency. These needs for information require encounters/ transaction-level data at the service level that can be captured consistently across entities and providers, and that can be manipulated to create plan-, provider-, and population-based estimates.