The internal validity of observational study is often subject to debate. In this study, we define the counterfactuals as the unobserved sample and intend to quantify its relationship with the null hypothesis statistical testing (NHST). We propose the probability of a robust inference for internal validity, that is, the PIV, as a robustness index…

Research Findings: This study used data from a national sample to examine differences in school outcomes at the end of kindergarten between Head Start children who attended full-day and half-day programs. Propensity scores were used to match children who experienced different intensities of the program on a series of demographic characteristics in…

Children's decisions regarding the allocation of societal resources in the context of preexisting inequalities were investigated. African American and European American children ages 5 to 6 years (n = 91) and 10 to 11 years (n = 94) judged the acceptability of a medical resource inequality on the basis of race, allocated medical supplies,…

Using data from the Early Childhood Longitudinal Study-Birth Cohort (n ˜ 6,950), a nationally representative sample of children born in 2001, we examined school readiness (academic skills and socioemotional well-being) at kindergarten entry for children who attended Head Start compared with those who experienced other types of child care…