Table 3.

Propensity Score Matching Results (ATT) Estimating the Effect of Age at First Birth on Age 40 Self-assessed Health among Women with a First Birth between Ages 15 and 19 (National Longitudinal Survey of Youth, 1979).

Variable	Self-assessed Health at Age 40
	Black Women	White Women	Hispanic Women
	ATT	ATT	ATT
Panel A: First birth ages 15–19 compared to ages 25–35
First birth ages 15–19	−.35**	−.14	−.05
(0 = first birth ages 25–35)	(.11)	(.09)	(.18)
Treatment observations	431	347	254
Control observations	207	758	182
Total n	638	1,105	436
Mean % bias	4.0%	5.3%	4.7%
Gamma (Γ)	1.2	—	—
Panel B: First birth ages 20–24 compared to ages 25–35
First birth ages 20–24	−.25*	−.18*	−.08
(0 = first birth ages 25–35)	(.11)	(.08)	(.15)
Treatment observations	323	512	242
Control observations	207	758	182
Total n	523	1,270	424
Mean % bias	5.2%	4.3%	5.3%
Gamma (Γ)	1.5	1.2	—
Panel C: First birth ages 20–24 compared to ages 15–19
First birth age 20–24	.10	−.00	.03
(0 = first birth ages 15–19)	(.10)	(.09)	(.13)
Treatment observations	322	502	241
Control observations	491	363	261
Total n	813	865	502
Mean % bias	4.1%	4.1%	3.7%

Note: Standard errors in parentheses. ATT = average treatment effect for the treated. Mean % bias is the average bias in covariate balance after matching. Gamma (Γ) is the factor by which an unobserved covariate must cause the odds ratio of treatment assignment to differ between treatment and control cases in order for the estimated treatment effect to no longer be statistically significant.

^*p <.05

^**p <.01

^***p <.001 (two-tailed tests).