The impact of non-parental child care on child development: Evidence from the summer participation “dip”

•This paper studies the effect of child care on preschoolers' mental development.•Identifying variation is provided by seasonal variation in child care participation.•OLS results show that children in child care score higher on mental ability tests.•However, the IV estimates point to sizeable negative effects of non-parental care.

Although a large literature examines the effect of non-parental child care on preschool-aged children's cognitive development, few studies deal convincingly with the potential endogeneity of child care choices. Using a panel of infants and toddlers from the Birth cohort of the Early Childhood Longitudinal Study (ECLS-B), this paper attempts to provide causal estimates by leveraging heretofore unrecognized seasonal variation in child care participation. Child assessments in the ECLS-B were conducted on a rolling basis throughout the year, and I use the participation “dip” among those assessed during the summer as the basis for an instrumental variable. The summer participation dip is likely to be exogenous because ECLS-B administrators strictly controlled the mechanism by which children were assigned to assessment dates. The OLS results show that children utilizing non-parental arrangements score higher on tests of cognitive ability, a finding that holds after accounting for individual fixed effects. However, the instrumental variables estimates point to sizeable negative effects of non-parental care. The adverse effects are driven by participation in formal settings, and, contrary to previous research, I find that disadvantaged children do not benefit from exposure to non-parental care.