Project Summary/Abstract This proposal seeks continued funding to expand and improve IPUMS CPS, an essential data resource for research on population health and child well-being in the United States. IPUMS CPS streamlines access and reduces technical barriers to analyzing data from the Current Population Survey (CPS), the nation's most comprehensive source of data on the economic and social well-being of U.S. individuals and families, including women of reproductive age and children. IPUMS CPS enables rigorous and reproducible research on population dynamics and the social and economic contexts in which health inequities are created and reinforced, enabling public policy based on sound scientific evidence. Building on an impressive record of accomplishments since 2016, the project will undertake new initiatives to ensure broad access, timely delivery, and innovative use of CPS data for population dynamics and population health research. The project has five specific aims: (1) Database expansion to add more than eight million person records by incorporating 65 new files that will be released between 2021 and 2026, including all CPS monthly and supplement data; (2) Data and metadata improvement to enhance research opportunities, reproducibility, and rigor; (3) Data access improvements to allow users to specify the combinations of CPS data they want linked and the formats in which they will receive the data; (4) Data processing tool enhancement to reduce the time to deliver new data to the research community and reduce the costs of maintaining the infrastructure over the long run; (5) Expand and support the research community through targeted, thoughtful outreach, and active user support and training. CPS data are indispensable for analyzing demographic topics identified in the core mission of the NICHD Population Dynamics Branch, including fertility, migration, population distribution, nuptiality, family demography, population growth and decline, and the causes and consequences of demographic change. They also contain rich measures of the most important non-clinical determinants of health and health inequities. The CPS is vital for evaluating the consequences of social safety net policies for children, individuals, and families; the impact of labor market disruption on marital transitions; and the implications of marital dissolution for economic well-being. With data on entire households, analyses of individual-, couple-, family-, and household-level dynamics are possible. Timely, user-friendly CPS data on the economic and social well-being of the U.S. population has never been more urgently needed.