Assessing the Value of the NHIS for Studying Changes in State Coverage Policies: The Case of New York



Research Objective. (1) To assess the effects of New York's Health Care Reform Act of 2000 on the insurance coverage of eligible adults and (2) to explore the feasibility of using the National Health Interview Survey (NHIS) as opposed to the Current Population Survey (CPS) to conduct evaluations of state health reform initiatives.

Study Design. We take advantage of the natural experiment that occurred in New York to compare health insurance coverage for adults before and after the state implemented its coverage initiative using a difference-in-differences framework. We estimate the effects of New York's initiative on insurance coverage using the NHIS, comparing the results to estimates based on the CPS, the most widely used data source for studies of state coverage policy changes. Although the sample sizes are smaller in the NHIS, the NHIS addresses a key limitation of the CPS for such evaluations by providing a better measure of health insurance status. Given the complexity of the timing of the expansion efforts in New York (which encompassed the September 11, 2001 terrorist attacks), we allow for difference in the effects of the state's policy changes over time. In particular, we allow for differences between the period of Disaster Relief Medicaid (DRM), which was a temporary program implemented immediately after September 11th, and the original components of the state's reform efforts—Family Health Plus (FHP), an expansion of direct Medicaid coverage, and Healthy New York (HNY), an effort to make private coverage more affordable.

Data Sources. 2000–2004 CPS; 1999–2004 NHIS.

Principal Findings. We find evidence of a significant reduction in uninsurance for parents in New York, particularly in the period following DRM. For childless adults, for whom the coverage expansion was more circumscribed, the program effects are less promising, as we find no evidence of a significant decline in uninsurance.

Conclusions. The success of New York at reducing uninsurance for parents through expansions of both public and private coverage offers hope for new strategies to expand coverage. The NHIS is a strong data source for evaluations of many state health reform initiatives, providing a better measure of insurance status and supporting a more comprehensive study of state innovations than is possible with the CPS.