Is Medicaid misreporting stable over time? Self-reported health insurance coverage of Medicaid recipients in Louisiana, 2007–2017

This study investigates individual-level misreporting among Medicaid recipients in Louisiana from 2007 to 2017. It explores whether the type of individual who misreports varies over time, including following a major policy shift (the implementation of the Affordable Care Act). Results are based on a series of biennial Medicaid Bias Studies from 2007 to 2017 in which Medicaid recipients are asked about their health care coverage, allowing us to identify individuals who misreport their status. Study participants are (1) randomly selected from state Medicaid files or (2) matched participants from a statewide health insurance survey designed to estimate uninsured rates. Survey respondents are asked a battery of questions designed to identify health insurance coverage for themselves and for each member residing within their household. Responses are then matched to Medicaid enrollment data to identify misreporting, including whether household members are misreported as uninsured, covered by an employer, or covered by some other government program. The results reveal that the level of Medicaid misreporting varies over time and that misreporting declined significantly following the Louisiana’s Medicaid expansion. As a result, careful estimation of Medicaid misreporting continues to be an important source of bias in estimates of health insurance coverage.