• Medicaid expansions;
  • health care reform;
  • health insurance

Objectives. To examine the impact of a Wisconsin health care reform enacted in early 2008 on public insurance enrollment and retention.

Data Sources. Administrative data covering the period January 2007 to November 2009.

Study Design. We calculate unadjusted enrollment trends and exit rates stratified by age, income group, and enrollment mode. Kaplan–Meier curves and Cox proportional hazards models are estimated to assess the impact of the reform on program exits.

Principal Findings. Overall enrollment increased by approximately one-third and exit rates decreased by approximately one-fifth. The majority of new enrollment came from the previously income eligible.

Conclusions. Wisconsin's enactment of eligibility expansions coupled with administrative simplification and targeted marketing and outreach efforts were successful in enrolling and retaining low-income children and families in public coverage.