Panel Paper: The Effect of WIC on Food and Income Security

Thursday, November 6, 2014 : 1:20 PM
Acoma (Convention Center)

*Names in bold indicate Presenter

Sarah Martin-Anderson, University of Missouri, Kansas City
The Special Supplemental Food and Nutrition Program for Women, Infants and Children (WIC) is a federal transfer program that aims to improve the health status of the country’s nutritionally at-risk by increasing the consumption of WIC-approved foods. Pregnant and nursing women, as well as their children age zero to five, are eligible pending income qualification and designation of nutritional “at-risk” status. The market value of the WIC food package is roughly 35 dollars per person for this paper’s study period and averaged 90 dollars per WIC household.

The literature on WIC suggests a protective effect against food insecurity for participating children, though the strength of this association is debatable. WIC research is often criticized, like much of the research on voluntary safety net programs, on the grounds of endogeneity bias. This refers to the immeasurable, inherent qualities that predict selection into treatment that may also predict outcomes.

Bearing in mind the potential for endogeneity bias, this study employs a regression discontinuity design focusing on a child’s age as the running variable. I am interested in exploiting the maturation from age 0 to 1 in order to identify potential income effects of WIC. The market value of the WIC basket declines significantly at age 1 with the removal of the infant formula component (the most economically valuable). I will also exploit the aging from 5 to 6 years of age when children age out of the program, investigating changes in food security at the household level, since previous research (VerPloeg 2007, Robinson 2009 and Martin-Anderson 2013) supports a spillover benefit from eligible to ineligible family members. Subgroup analysis will determine how sensitive the findings are to household demographics—I am especially interested in how the relationship between WIC and household security changes along the income spectrum and whether the relationship changes across SIPP waves.

This paper uses the Study of Income and Program Participation (SIPP). The SIPP is a longitudinal dataset following a nationally representative sample of households over a period of roughly 4 years (for more information on SIPP see I restrict my study only to households with children ages 0-5 when the study wave begins and that are income-eligible for WIC by household size. I combine multiple waves in this study in order to increase the statistical power of the analysis.

Preliminary analysis suggests that there is no discernible income or food security effect of WIC for income-eligible households overall. However, for those on the lowest end of the economic spectrum (those making between 0 and 50% of the Federal Poverty Level), there does appear to be significant increases in food insecurity as a function of aging out of the WIC program.