Cover: Do Medicaid and Commercial CAHPS Scores Correlate Within Plans?

Do Medicaid and Commercial CAHPS Scores Correlate Within Plans?

A New Jersey Case Study

Published 2005

by Marc N. Elliott, Donna O. Farley, Katrin Hambarsoomian, Ron D. Hays

Download Free Electronic Document

FormatFile SizeNotes
PDF file 0.1 MB

Use Adobe Acrobat Reader version 10 or higher for the best experience.

BACKGROUND: The Consumer Assessment of Health Plans Study (CAHPS) health plan survey is currently administered to large independent samples of Medicaid beneficiaries and commercial enrollees for managed care organizations that serve both populations. There is interest in reducing survey administration costs and sample size requirements by sampling these 2 groups together for health plan comparisons. Plan managers may also be interested in understanding variability within plans. OBJECTIVE: The objective of this study was to assess whether the within plan correlation of CAHPS scores for the 2 populations are sufficiently large to warrant inferences about one from the other, reducing the total sample sizes needed. RESEARCH DESIGN: This study consisted of an observational cross-sectional study. SUBJECTS: Subjects were 3939 Medicaid beneficiaries and 3027 commercial enrollees in 6 New Jersey managed care plans serving both populations. MEASURES: Outcomes are 4 global ratings and 6 report composites from the CAHPS 1.0 survey. RESULTS: Medicaid beneficiaries reported poorer care than commercial beneficiaries for 6 composites, but none of the 4 global ratings. Controlling for these main effects, variability between commercial enrollees and Medicaid beneficiaries within plans exceeded variability by plans for commercial enrollees for 4 of the 10 measures (2 composites, 2 global ratings). CONCLUSIONS: Within-plan variability in evaluations of care by Medicaid and commercial health plan member evaluations is too great to permit meaningful inference about plan performance for one population from the other for many important outcomes; separate surveys should still be fielded.

Originally published in: Medical Care, v. 43, no. 10. October 2005, pp. 1027-1033.

This report is part of the RAND reprint series. The Reprint was a product of RAND from 1992 to 2011 that represented previously published journal articles, book chapters, and reports with the permission of the publisher. RAND reprints were formally reviewed in accordance with the publisher's editorial policy and compliant with RAND's rigorous quality assurance standards for quality and objectivity. For select current RAND journal articles, see External Publications.

This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit

RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.