Impact of Head Start on Children with Disabilities: Evidence from the Head Start Impact Study
*Names in bold indicate Presenter
This study uses data from the Head Start Impact Study (HSIS) to examine the impact of Head Start on children with disabilities. As the only large-scale randomized experiment in Head Start history, the HSIS included a nationally representative sample of 3- and 4-year-old children who were eligible for Head Start. Children in the HSIS control group received a mixture of alternative care arrangements, including another Head Start program, other center-based care, and informal care (i.e., relative/non-relative care and parental care). A preliminary analysis of the HSIS full sample shows that the effects of Head Start vary substantially depending on the counterfactual care arrangement.
This study first investigates whether Head Start has beneficial effects on children with disabilities in preschool year, kindergarten, first grade, and third grade, compared to other center-based care and informal care. Further analyses are conducted to compare whether the effects of Head Start on children with disabilities are different from those on children without disabilities. The cognitive outcomes were collected from direct assessments, including Peabody Picture Vocabulary Test (PPVT) Receptive Vocabulary and Woodcock-Johnson III Letter-Word Identification and Applied Problems. The behavioral outcomes were reported by parents, including Aggressive Behavior and Hyperactive Behavior. Among 4,442children in HSIS, 755 children had identified disabilities or special needs, including 417 in the 3-year cohort and 338 in the 4-year cohort.
There is an issue of selection since children in the HSIS control group chose different care arrangements, and similarly, children in the treatment group would also have chosen different arrangements if they had been assigned to the control group. OLS regressions are first conducted to control for pretreatment covariates. To further address the issue of selection, principal score matching is used to first estimate the probabilities of choosing different care arrangements for children in the control group, and then apply the predicted parameters to the treatment group to estimate the probabilities of having these arrangements for Head Start participants if they had been assigned to the control group. Children with similar principal scores are then matched and their outcomes are compared. The findings of this study may provide important implications regarding whether children with disabilities would benefit from Head Start in the short and long terms and whether the benefits are greater for these children than for their peers without disabilities.