ABSTRACT A recent global estimate suggests that nearly 250 million young children fail to reach their cognitive potential, leading to widening gaps in health and human capital as these children become adults. Many children who fail to meet their potential have suffered from major life events that lead to downward spirals in health, cognitive development, and ultimately lower human capital accumulation. China’s major social, economic, and demographic transitions have led to more than a third of all children and adolescents in rural China who are left behind by one or both parents who migrate for job opportunities. Yet, there are fundamental gaps in understanding: (1) the mechanisms through which such major life events affect health and development; and (2) the moderating and mediating factors that may buffer these impacts on human capital. The China Health and Nutrition Survey (CHNS) is an NIH-funded study of more than 41,000 individuals followed over 35 years, capturing dramatic and rapid modernization- and environment-related changes in individual, household and community environments. The CHNS offers high quality, unique and extraordinary, intergenerational data that capture the interdependent biological, health, social, and environmental factors that affect child development over time and under conditions of enormous environmental change (e.g., the end of the one-child policy, migration of adults to seek work, leaving their children behind with grandparents, and closures of village schools sending children away from their families to attend boarding schools). We propose data collection from individuals aged 0-45 years in an additional round in 2021, preserving the continuity of CHNS, while adding new measures of age-specific cognitive and non-cognitive skills, parental, school and community investments. We propose data collection and dissemination of this ongoing and valuable public resource. These data will provide the unique opportunity to understand complex biological, social, and environmental dynamics of multiple dimensions of human capital in context of new social, economic and demographic shifts. We propose to identify life-stage-specific exposures that predict cognitive function, school attainment, and height and test hypotheses about how investments in health, nutrition, and education shape human capital and foster resilience in the face of rapid changes. In addition, we propose to identify how changing dietary patterns, including intakes of sodium, potassium, and “modern diets” relate to body mass, waist circumference, and blood pressure from youth into adulthood (ages 0-45 years). Adding an 11th wave of multipurpose data will augment the already high value and utility of the CHNS, by including an expanded focus on cognitive and non- cognitive skills, parental, school and community investments, allowing for the study of the dynamics and early life antecedents of human capital accumulation, with a focus on modifiable factors with pote...