Project Summary/Abstract The Panel Study of Income Dynamics (PSID) is a longitudinal survey of a nationally-representative sample of U.S. families that began in 1968. In 1997 PSID began to collect extensive data on children in the sample as part of the original PSID Child Development Supplement (CDS-I), which followed a cohort of PSID children aged 0?12 years. A second wave was collected on these same children in 2002/03 (CDS-II) when they were aged 5?18 years and a third wave was collected in 2007/08 (CDS-III) for children in this cohort who were aged 10?18 years. By 2014, children in the original CDS cohort had reached adulthood, and CDS was relaunched as ongoing study in which data collection is planned at regular 5?6 year intervals on all children aged 0?17 years in PSID families. The first round of the ongoing CDS was fielded in 2014?2015, and the next round is planned for 2019?2020. In all waves of CDS, extensive data on children's development, health, and wellbeing were collected from children's primary caregivers (PCGs, typically each child's mother) and from interviews with older children (aged 8+ years). A variety of additional information was collected in all rounds of CDS, in- cluding weekday and weekend time diaries, anthropometric measurements, home and neighborhood observa- tions, and saliva samples for subsequent genetic analysis (in CDS-2014). All of these data have been pro- cessed and documented and are being distributed?free of charge?to the research community through the PSID Online Data Center. In this project, we will create a new CDS Online Data Center, a public data archive that focuses exclusively on CDS and provides important new functions and enhancements that will help re- searchers use data from CDS efficiently and effectively with minimal start-up time. The specific aims of this project are to: (1) design and construct a new CDS Online Data Center to provide new and established data users with easier access to all waves of the original CDS and the new ongoing CDS; (2) enhance the new CDS Online Data Center through added functionality that allows data users to easily incorporate data from Core PSID about children's household, family, and parent characteristics throughout their lifetimes; and (3) publicize the availability of the new CDS Online Data Center to current and prospective data users. This project is sub- mitted in response to PAR-16-149, ?Archiving and Documenting Child Health and Human Development Data Sets,? and responds directly to the specific interest of NICHD in ?Creating data extraction web tools for public use databases, such as?the Panel Study of Income Dynamics Child Development Supplement.? This project will facilitate secondary analysis by the scientific community of data within the scientific mission of NICHD and collected with NICHD support.