The impact of CHIP on children's insurance coverage: an analysis using the National Survey of America's Families.

Abstract

To assess the impact of the Children's Health Insurance Program (CHIP) on the distribution of health insurance coverage for low-income children. The primary data for the study were from the 1997, 1999, and 2002 National Survey of America's Families (NSAF), which includes a total sample of 62,497 children across all 3 years, supplemented with data from other data sources. The study uses quasi-experimental designs and tests the sensitivity of the results to using instrumental variable and difference-in-difference approaches. A detailed Medicaid and CHIP eligibility model was developed for this study. Balanced repeated replicate weights were used to account for the complex sample of the NSAF. Descriptive and multivariate analyses were conducted. The results varied depending on the approach utilized but indicated that the CHIP program led to significant increases in public coverage (14-20 percentage points); and declines in employer-sponsored coverage (6-7 percentage points) and in uninsurance (7-12 percentage points). The estimated share of CHIP enrollment attributable to crowd-out ranged from 33 to 44 percent. Smaller crowd-out effects were found for Medicaid-eligible children. Implementation of the CHIP program resulted in large increases in public coverage with estimates of crowd-out consistent with initial projections made by the Congressional Budget Office. This paper demonstrates that public health insurance expansions can lead to substantial reductions in uninsurance without causing a large-scale erosion of employer coverage.