Understanding the nature and mechanisms of early inputs' impacts on child outcomes is central to current research. Leveraging administrative data, the present study estimated a home-visiting parenting program's impacts (2,000 participating children age 3-4; 35% Black; 30% White; 32% Hispanic; 48% female). The program generated a 0.07 SD gain on cognitive skills at kindergarten entry; increased the likelihood of uptake in services under IDEA and decreased child maltreatment by two percentage points in both cases. Results were robust to conditioning on preschool attendance. Null hypotheses for home-visiting and preschool interactions could not be rejected, suggesting that the change in parent-child interactions from participation in the home-visiting parenting program yielded different skills from those developed through participation in voluntary prekindergarten.