PROJECT SUMMARY An urgent child policy question facing the U.S. concerns how much and in what way to invest in early care and education, particularly pre-kindergarten (pre-k). Rigorous evaluations of pre-k programs within states have produced positive, negative, and null findings that are difficult to reconcile, necessitating an approach that can integrate data across time and contexts. We ask whether variations in investments by the 50 states across the past 20 years are associated with better child health, achievement, and family outcomes. Our study will build on our previous work in North Carolina (NC), which examined the effect of variation in pre-k funding to counties across years on child outcomes using econometric analyses of panel data. Our first aim is to evaluate whether the beneficial impacts of investments in public pre-k generalize across the nation and with other estimation approaches. We will use this rigorous method at the national level by compiling the first state-by-year-level dataset that integrates pre-k funding, pre-k program features, state characteristics, and child and family outcomes (e.g., NAEP scores, anxiety, disability, maternal employment), applying a state- and year-fixed effects approach. We also incorporate new NC data for an instrumental variables approach, using the interaction between a family’s proximity to the nearest NC Pre-K center and funding for pre-k as an instrument for pre-k attendance—providing innovative causally-informative evidence of pre-k effects. The second aim is to determine whether statewide investments in pre-k promote children’s well-being across different subgroups. In our nationwide study, we will test whether state investment levels have differential impact on subgroups of children, and in NC, we will test whether our new analytic approaches demonstrate beneficial impacts on child achievement for all populations of children. The third aim is to examine whether features of state pre-k programs and children’s environments are associated with differential impact of states’ investments, which we test through moderation analyses of carefully collected pre-k implementation data in each state and year. The fourth aim is to examine whether prior NC Pre-K exposure protected children from the adverse impact of economic shocks and natural disasters, by contrasting academic achievement for NC Pre-K attenders with a matched group of non-attenders during pre- and post-economic crises, and from counties affected by hurricanes, floods, and snowstorms. Together, this work will inform child development theory about the enduring impact of early education experiences and optimal policy strategies for promoting positive learning outcomes.