Bitler MP, Currie J. Does WIC work? The effects of WIC on pregnancy and birth outcomes. J Policy Anal Manage. Winter 2005;24(1):73-91.
This paper evaluated the skepticism that WIC research failed to properly control for selection into the WIC Program, using rich data from the national Pregnancy Risk Assessment Monitoring System. The authors showed that relative to Medicaid mothers, all of whom were eligible for WIC, WIC participants were negatively selected on a wide array of observable dimensions, yet WIC participation was associated with improved birth outcomes.