In 1999, quality in primary care will be measured more closely than ever before. Quality will not only be measured—but also reported—and reported in a form that consumers can use to compare health plans. A health plan's accreditation will depend on its performance on a series of 14 performance measures, referred to as theHealth Plan Employer DataandInformation Set, Version 3.0 (HEDIS 3.0), which the National Committee for Quality Assurance, an organization that accredits health plans, has developed, quantified, refined, and publicized. This article introduces the primary care clinician to HEDIS quality measures and recommends tools clinicians can use to score well in performance evaluations.