Validating health insurance coverage survey estimates - A comparison of self-reported coverage and administrative data records

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.