The effect of the children's health insurance program on pediatricians' work hours.

Objective: Our study examines changes in physicians' work hours in response to a coverage expansion.

Methods: We use as a natural experiment the Children's Health Insurance Program (CHIP), which was established in 1997 and significantly expanded children's eligibility for public health insurance coverage. The magnitude of the CHIP expansion varied across states and over time, allowing its effects to be identified using a state-year fixed effects model. We focus on pediatricians, and we measure their self-reported work hours using multiple waves (pre- and post-CHIP) of the physician survey component of the Community Tracking Study. To address endogeneity concerns, we instrument for CHIP enrollment using key program features (income eligibility cutoffs and waiting times).

Results: We find a large negative relationship between the magnitude of a state's CHIP expansion and trends in pediatricians' work hours. This relationship could be due to key supply-side features of CHIP, including relatively low provider reimbursements and heavy use of managed care tools.