Attending high-quality early childhood care and education (ECCE) is associated with higher cognitive and social-emotional skills, especially for children growing up in poverty, but access to high-quality ECCE is limited. This study capitalizes on the random assignment design of the Head Start Impact Study to better understand whether the…

Researchers have become increasingly interested in programs' main and interaction effects of two variables (A and B, e.g., two treatment variables or one treatment variable and one moderator) on outcomes. A challenge for estimating main and interaction effects is to eliminate selection bias across A-by-B groups. I introduce Rubin's causal model to…