Validation of Two Federal Health Insurance Survey Modules after Affordable Care Act Implementation

This study randomized a sample of households covered by one large health plan to two different surveys on health insurance coverage and matched person-level survey reports to enrollment records. The goal was to compare accuracy of coverage type and uninsured estimates produced by the health insurance modules from two major federal surveys - the redesigned Current Population Survey Annual Social and Economic Supplement (CPS) and the American Community Survey (ACS) - after implementation of the Affordable Care Act. The sample was stratified by coverage type, including two types of public coverage (Medicaid and a state-sponsored program) and three types of private coverage (employer-sponsored, non-group, and marketplace plans). Consistent with previous studies, accurate reporting of private coverage is higher than public coverage. Generally, misreporting the wrong type of coverage is more likely than incorrectly reporting no coverage; the CPS module overestimated the uninsured by 1.9 and the ACS module by 3.5 percentage points. Other differences in accuracy metrics between the CPS and ACS are relatively small, suggesting that reporting accuracy should not be a factor in decisions about which source of survey data to use. Results consistently indicate that the Medicaid undercount has been substantially reduced with the redesigned CPS.