WIC Participation Patterns: An Investigation of Delayed Entry & Early Exit
by Laura Tiehen
and Alison Jacknowitz
Economic Research Report No. (ERR-109) 45 pp, December 2010
What Is the Issue?
Despite the health benefits of participation, many eligible
households do not participate in USDA's Special Supplemental
Nutrition Program for Women, Infants, and Children (WIC). While
roughly half of infants born in the United States receive WIC
benefits, USDA statistics indicate that eligible pregnant women and
children 1-5 years of age are far less likely to participate in WIC
than eligible infants and postpartum women. This implies that a
number of pregnant women delay enrollment until after having a
child, and that many households leave the program when a
participating child turns 1 year old. Research on the factors that
influence the dynamics of WIC participation can inform outreach and
targeting efforts, so that vulnerable populations receive adequate
exposure to the benefits of WIC participation.
What Did the Study Find?
There are notable differences in the timing of household
participation in the WIC program.
- Among the mother-child pairs (referred to as households)
eligible for WIC, 79.1 percent
participated in the program at some time during the period between
the child's birth and when the child turned 1 year old (the
- Of those who participated in the WIC program during the
postnatal-infant period, 17.6
percent did not enroll in the program until after the child was
born and 22.9 percent exited the program when the child turned 1
Postnatal Enrollment in WIC
The following types of households were more likely than others
to delay participating in WIC
until after their child was born:
- Households with higher income and those with private
- Households in which the mother has a college degree and was
employed the year before
- Households in the Northeast and those in urban areas with a
population of at least 50,000.
By contrast, prenatal Medicaid recipients were much less likely
to delay WIC enrollment until
after having a child.
Exits From WIC
When a child turns 1 year old, the WIC household must recertify
its eligibility for benefits. Roughly 90 percent of
postnatal-infant participants retained eligibility after the child
turned 1 year old. The following types of households were more
likely than others to exit WIC after their child turns 1 year
- Households with higher income.
- Households in which mothers are more educated and were employed
after the child's birth.
- Mothers who did not breastfeed and those who breastfed for less
than 6 months.
By contrast, households with income below the poverty line and
those that participated in prenatal Medicaid were less likely to
exit WIC after their child turned 1 year old. Approximately 33
percent of households that left the WIC program reported that they
believed they were no longer eligible once the child turned 1 year
old, and 27.8 percent reported that they no longer needed food
When a child turns 1 year old, the eligible WIC household no
longer receives the infant food package, which contains infant
formula for those who are not being breastfed exclusively, and
transitions to the child food package, which has a significantly
lower retail value. This change in WIC food benefits may play a
role in a household's decision to exit WIC.
Although WIC is not an entitlement program, few households
reported that they were denied benefits due to lack of program
funds. Some households reported, however, that the program requires
too much effort and the benefits are not worth the time (26.2
percent of those exiting) or that they have scheduling and
transportation problems (almost 10 percent of those exiting),
suggesting that such transaction costs of participation may be a
barrier to continued participation in WIC.
How Was the Study Conducted?
Researchers used data from the Early Childhood Longitudinal
Study-Birth Cohort (ECLS-B), a nationally representative
longitudinal dataset of children born in 2001. The dataset provides
demographic and economic information collected from the child's
biological mother when the child is 9 months and 24 months old, as
well as information from the child's birth certificate. The ECLS-B
collects extensive information about the WIC participation of the
mother and children in the household, and the timing of that
participation. In addition, a subset of mothers who left the
WIC program was asked to report why they stopped receiving WIC
benefits for their child.
The researchers used probit regression analysis to examine the
factors that influence postnatal, rather than prenatal, enrollment
in WIC and the factors that influence a household's exit from WIC
once the child turns 1 year old. The researchers' analysis focused
on the factors that influence a household's participation:
perceived benefits, the stigma or transaction costs associated with
participation, and the availability of information on the program
and its eligibility
requirements. The researchers also used multinomial logit
regression to examine WIC household characteristics that may have
influenced WIC participants' self-reported explanation for leaving