Long-term impact evaluation of early childhood conditions When only short-term outcomes are available

Over the past two decades, socio-economic research has highlighted and empirically demonstrated the importance of investing in early childhood development for long-term life outcomes. In response, governments and foundations have increasingly allocated resources to preschool initiatives, promoting formal childcare, encouraging access to libraries and playrooms, and facilitating parent-child activities aimed at enhancing parenting skills. While the short-term effects of many of these policies are frequently assessed, evaluating their long-term impact remains challenging due to high costs and logistical complexities. How can meaningful insights into long-term effects be derived when only short-term outcomes are available? Adopting the "surrogacy" framework proposed by Athey et al. (2024) and using data from the Millennium Cohort Study (UK), we predict long-term outcomes assuming only short-term outcomes are available, and compare them with the actual ones. This analysis introduces a valuable tool for policymakers and program evaluators, helping to identify key outcome variables for impact assessment and the prediction of long-term effects.