Context: Accreditation of health care organizations has traditionally been considered a building block of quality assurance. However, the differences between accredited and nonaccredited health plans and the impact of accreditation on plan enrollment are not well understood.
Objectives: To determine the characteristics of plans that have submitted to accreditation review, the performance of accredited plans on quality indicators and the impact of accreditation on enrollment.
Design: The databases containing 1996 data on health plans' National Committee on Quality Assurance (NCQA) accreditation status, organizational characteristics, Health Plan Employer Data and Information Set (HEDIS) scores, and patient-reported quality and satisfaction scores were linked to compare accredited health plans to nonaccredited plans. We also combined longitudinal data sets (1993-1998) on accreditation and health plan enrollment.
Main outcome measures: Mean performance of accredited and nonaccredited plans on HEDIS measures and patient-reported measures of quality; health plan enrollment changes.
Results: Accredited plans have higher HEDIS scores but similar or lower performance on patient-reported measures of health plan quality and satisfaction. Furthermore, a substantial number of the plans in the bottom decile of quality performance were accredited suggesting that accreditation does not ensure high quality care. Receipt of accreditation has been associated with increased enrollment in the early years of the accreditation program; however, plans denied NCQA accreditation do not appear to suffer enrollment losses.
Conclusion: NCQA accreditation is positively associated with some measures of quality but does not assure a minimal level of performance. Efforts now underway to incorporate plan performance on HEDIS into criteria for accreditation seem warranted.