ACF OPRE: Head Start Impact Study and Follow-up

Appendix 7.1: Health Domain, Estimated Impact of Program Participation

As in previous chapters, Exhibits A.7.1.1 and A.7.1.2 provide impact estimates that are adjusted for the fact that some of the children assigned to Head Start failed to take advantage of this opportunity—i.e., they never participated in Head Start (the “no shows”)-and that some children assigned to the non-Head Start group managed to find their way into the program (the “crossovers”). All measures of the impact of participation in Head Start exceeded the corresponding measures of the average impact of access to Head Start, regardless of which adjustment method was used. For example, the first row of Exhibit A.7.1.1 shows an estimated impact of 0.17 on whether the child received dental care for the average child in the 3-year-old group granted access to the program through assignment to the Head Start research sample, and a larger average impact of 0.19-0.26 for those children who actually attended Head Start. These same increases are again seen in the relationship between the calculated effect sizes for the estimates of “access” vs. “participation,” with a few instances of the size of the effect moving from “modest” (between 0.2 and 0.5) to “large” (over 0.5).

These data provide an indication of the dampening effect of the crossover children in the non-Head Start group, i.e., reducing the size of any observed difference in outcomes between the Head Start and non-Head Start groups. But, again, the combined no-show/crossover adjustments should only be used as a rough indication of the likely consequences of the presence of crossovers on the interpretation of the impact of Head Start on children’s school readiness.

Exhibit A.7.1.1: Initial Estimates of the Impact of Head Start on Health Outcomes, Intent to Treat, and Impact on the Treated: Statistically Significant Results Only, 3-Year-Old Group, Combined English-English and Spanish-English Group (Weighted Data)
Outcome Measure		Impact Estimates			Effect Sizes
Outcome Measure		Impact of Access to Head Start	Impact of Head Start Participation, No-Show Adjustment	Impact of Head Start Participation, Combined No-Show and Crossover Adjustment	Impact of Access to Head Start	Impact of Head Start Participation, No-Show Adjustment	Impact of Head Start Participation, Combined No-Show and Crossover Adjustment
Overall Impact	Child Health Status Excellent or Very Good	0.05*	0.06*	0.06*	0.12	0.14	0.14
Overall Impact	Child Had Dental Care	0.17***	0.19***	0.26***	0.34	0.38	0.52
Difference in Impact 1	Child Health Status: Home Language (Non-English Impact Exceeds English)	0.12*	0.14*	N/A	0.28	0.33	N/A
	Child Health Status: Depression	0.05*	0.06*	N/A	0.12	0.14	N/A
	Child Had Care for Injury: Race (White Impact Exceeds African American)	0.08*	0.09*	N/A	0.30	0.33	N/A
	Child Had Care for Injury: Race (White Impact Exceeds Hispanic)	0.13***	0.15***	N/A	0.48	0.56	N/A
	Child Had Dental Care: Depression	0.16***	0.18***	N/A	0.32	0.36	N/A
Impact on Subgroup 2	Child Health Status: Special Needs	0.19*	0.21*	N/A	0.44	0.49	N/A
	Child Health Status: Parent Married	0.08*	0.09*	N/A	0.19	0.21	N/A
	Child Health Status: Hispanic	0.12**	0.14**	N/A	0.28	0.33	N/A
	Child Health Status: Home Language Not English	0.14**	0.16**	N/A	0.33	0.37	N/A
	Child Had Care for Injury: White	0.07***	0.08***	N/A	0.26	0.30	N/A
	Child Had Care for Injury: Hispanic	-0.06*	-0.07*	N/A	- 0.22	- 0.26	N/A
	Child Had Dental Care: Special Needs	0.24*	0.26*	N/A	0.48	0.52	N/A
	Child Had Dental Care: No Special Needs	0.16***	0.18***	N/A	0.32	0.36	N/A
	Child Had Dental Care: Parent Married	0.18***	0.21***	N/A	0.36	0.42	N/A
	Child Had Dental Care: Parent Not Married	0.16***	0.18***	N/A	0.32	0.36	N/A
	Child Had Dental Care: White	0.17***	0.19***	N/A	0.34	0.38	N/A
	Child Had Dental Care: Hispanic	0.22***	0.25***	N/A	0.44	0.50	N/A
	Child Had Dental Care: Home Language Not English	0.22***	0.25***	N/A	0.44	0.50	N/A
	Child Had Dental Care: Home Language English	0.15***	0.17***	N/A	0.30	0.34	N/A

* = p≤0.05, ** = p≤0.01, *** = p≤0.001.

1 A total of 35 differences in impacts between subgroups were examined. The complete set of results, including differences not found to be statistically significant, appears in Appendix 7.2. Findings for depression indicate the change in Head Start’s estimated impact that accompanies a 1-point increase in mother’s baseline depression score. Findings for baseline factors other than depression indicate the amount by which Head Start’s estimated impact for the first subset of participants listed in the row label exceeds that for the second subset listed. (back)

2 A total of 50 subgroup impacts were examined. The complete set of results, including differences not found to be statistically significant, appears in Appendix 7.2. (back)

Exhibit A.7.1.2: Initial Estimates of the Impact of Head Start on Health Outcomes, Intent to Treat, and Impact on the Treated: Statistically Significant Results Only, 4-Year-Old Group, Combined English-English Spanish-English Group (Weighted Data)
Outcome Measure		Impact of Access to Head Start	Impact of Head Start Participation, No-Show Adjustment	Impact of Head Start Participation, Combined No-Show and Crossover Adjustment	Impact of Access to Head Start	Impact of Head Start Participation, No-Show Adjustment	Impact of Head Start Participation, Combined No-Show and Crossover Adjustment
Overall Impact	Child Had Dental Care	0.16***	0.19***	0.23***	0.32	0.38	0.46
Difference in Impact 1	Child Had Health Insurance: Race (Hispanic Impact Exceeds African American)	0.08*	0.10*	N/A	0.24	0.30	N/A
	Child Health Status: Special Needs (No Special Needs Impact Exceeds Special Needs)	0.22*	0.26*	N/A	0.56	0.67	N/A
	Child Had Dental Care: Depression	0.16***	0.19***	N/A	0.32	0.38	N/A
Impact on Subgroup 2	Child Had Health Insurance: Home Language Not English	0.06*	0.07*	N/A	0.18	0.21	N/A
	Child Health Status: Special Needs	-0.23*	-0.26*	N/A	-0.59	-0.67	N/A
	Child Health Status: Parent Married	-0.08**	-0.10**	N/A	-0.21	-0.26	N/A
	Child Health Status: Home Language Not English	-0.08*	-0.09*	N/A	-0.21	-0.23	N/A
	Child Had Dental Care: No Special Needs	0.16***	0.19***	N/A	0.32	0.38	N/A
	Child Had Dental Care: Parent Married	0.18***	0.22***	N/A	0.36	0.44	N/A
	Child Had Dental Care: Parent Not Married	0.14**	0.17**	N/A	0.28	0.34	N/A
	Child Had Dental Care: White	0.24***	0.28***	N/A	0.48	0.56	N/A
	Child Had Dental Care: Hispanic	0.12*	0.14*	N/A	0.24	0.28	N/A
	Child Had Dental Care: Home Language Not English	0.17**	0.19**	N/A	0.34	0.38	N/A
	Child Had Dental Care: Home Language English	0.16***	0.20***	N/A	0.32	0.40	N/A

* = p≤0.05, ** = p≤0.01, *** = p≤0.001.

2 A total of 50 subgroup impacts were examined. The complete set of results, including differences not found to be statistically significant, appears in Appendix 7.2. (back)

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