Abstract
This paper estimates the causal impacts on child skills and the mechanisms producing these impacts using data from a randomized control experiment. We study a widely emulated early-childhood home visiting program and show the feasibility of replicating it at scale. We go beyond reporting treatment effects as unweighted item scores and assess item difficulties. To interpret treatment effects, we estimate individual-level latent skills and compare treatments and controls. The program substantially improves multiple skills. We decompose the source of treatment effects and find that enhancements in latent skills explain most of the conventional treatment effects for language and cognition.