Call, K. T., M. Davern, and L. A. Blewett. 2007. "Estimates of Health Insurance Coverage: Comparing State Surveys to the Current Population Survey." Health Affairs 26(1):269-78.

The Census Bureau produces annual state-level estimates of health insurance coverage using the Current Population Survey (CPS) Annual Social and Economic Supplement. Many states also conduct their own population surveys of health insurance status; in most cases, the state survey estimates of uninsurance are lower than the estimates produced by the CPS. This discrepancy fuels debate about the true count of uninsured Americans and changes in that number over time. This paper compares state survey and CPS estimates of uninsurance, highlights key reasons for these differences, and discusses the policy implications of this persistent discrepancy.