We administered a health insurance coverage survey module to a sample of 4,575 adult Blue Cross and Blue Shield of Minnesota (BCBS) members to examine if people who have health insurance coverage self-report that they are uninsured. We were also interested in whether respondents correctly classify themselves as having commercial, Medicare, MinnesotaCare, and/or Medicaid coverage (the four sample strata). The BCBS of Minnesota sample is drawn from both public and commercial health insurance coverage strata that are important to policy research involving survey data. Our findings support the validity of our health insurance module for determining whether someone who has health insurance is correctly coded as having health insurance coverage, as only 0.4 percent of the BCBS members answered the survey as though they were uninsured. However, we find problems for researchers interested in using survey responses to specific types of public coverage. For example, 21 percent of the Medicaid self-reported coverage came from known enrollees and only 67 percent of the MinnesotaCare self-reported count came from known enrollees. We conclude with a discussion of the study's implications for understanding the Medicaid "undercount" and the validity of self-reported health insurance coverage.
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MICHAEL DAVERN, KATHLEEN THIEDE CALL, JEANETTE ZIEGENFUSS, GESTUR DAVIDSON AND LYNN BLEWETT are with University of Minnesota. TIMOTHY J. BEEBE is with Mayo Clinic College of Medicine. An earlier version of this paper was presented at the American Association of Public Opinion Research Annual Meeting in Phoenix, AZ, May 2004 by Kathleen Thiede Call, and at the American Enterprise Institute on April 8, 2005 by Michael Davern. The authors are especially grateful to Pete Rode, Steven Foldes, Barb Schillo, Nina Alesci, Jessie Saul, and Ann Kinney for help in compiling the data. Also, the authors would like to thank Cathi Callahan of ARC, Linda Giannarelli of the Urban Institute, Peter Miller and the excellent reviewers for their comments on this paper, and Karen Soderberg for her editing assistance. Address correspondence to Michael Davern; firstname.lastname@example.org Preparation of this manuscript was funded by grant no. 038846 from the Robert Wood Johnson Foundation.