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Plan, Geographical, and Temporal Variation of Consumer Assessments of Ambulatory Health Care


  • Alan M. Zaslavsky,

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    • Address correspondence to Alan M. Zaslavsky, Ph.D., Department of Health Care Policy, Harvard Medical School, 180 Longwood Ave., Boston, MA 02115-5899. Paul D. Cleary, Ph.D., and Lawrence B. Zaborski, Ph.D., are also with the Department of Health Care Policy, Harvard Medical School.

  • Lawrence B. Zaborski,

  • Paul D. Cleary

  • This research was supported by a grant from the Commonwealth Fund to Paul D. Cleary and by a contract (#500-95-007) with the Centers for Medicare and Medicaid Services (CMS).


Objective. To quantify contributions of health plans and geography to variation in consumer assessments of health plan quality.

Data Sources. Responses of beneficiaries of Medicare managed care plans to the Consumer Assessment of Health Plans Study (CAHPS®) survey. Our data included more than 700,000 survey responses assessing 381 Medicare managed care (MMC) contracts over a period of five years.

Study Design. The survey was administered to a nationally representative sample of beneficiaries of Medicare managed care plans.

Principal Findings. Member assessments of their health plans, customer service functions, and prescription drug benefits varied most across health plans; these also varied the most over time. Assessments of direct interactions with doctors and their practices were more affected by geographical location, and these assessments were quite stable over time. A health plan's global rating often changed significantly between consecutive years, but only rarely were there such changes in ratings of care or doctor. Nationally, mean assessments tended to decrease over the study period.

Conclusions. Our findings suggest that ratings of plans and reports about customer service and prescription access are affected by plan policies, benefits design, and administrative structures that can be changed relatively quickly. Conversely, assessments of other aspects of care are largely determined by characteristics of provider networks that are relatively stable. A consumer survey is unlikely to detect meaningful changes in quality of care from year to year unless quality improvement measures are developed that have substantially larger effects, possibly through area-wide initiatives, than historical temporal variations in quality.