The Impact of Preschool Entry Age on Children’s Behavioral and Developmental Health in Medicaid

We thank Michael Darden, Bill Evans, Ari Ne’eman, Maria Polyakova, Lee Sanders, and participants at the Annual Health Economics Conference for helpful comments. We also thank Isabella Chu, Sun Young Jeon and David Rehkopf from the Stanford Center for Population Health Sciences (PHS) and Jens Hainmueller and the Stanford Immigration Policy Lab for assistance with accessing and using the Medicaid data at PHS. This study has been approved by Stanford’s Institutional Review Board (Protocol 68281). Sabety gratefully acknowledges grant support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (K01- HD113828-01A1) and the Yvette Gurley Research Scholar Fund. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. All errors are our own. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.

• January 7, 2026