The third national survey of child and adolescent well-being: Design overview and methodological lessons learned during the baseline wave.

• The National Survey of Child and Adolescent Well-Being (NSCAW) is the only source of nationally representative, longitudinal data on the well-being of children and families involved with the child welfare system. • The baseline data collection for the third cohort (NSCAW III) was completed in March 2022 and data have been archived for researchers. • Methodological and operational challenges faced during the baseline wave of NSCAW III required the identification and implementation of creative solutions for sampling, child welfare agency recruitment, instrumentation, data collection, and weighting. • This paper shares lessons learned and solutions from NSCAW III that may be relevant to other studies utilizing similar methods and/or collecting data from child welfare-involved populations. The National Survey of Child and Adolescent Well-Being (NSCAW) is a national survey that follows children and families who have been the subjects of investigation by child protective services agencies. NSCAW is the only source of nationally representative, longitudinal data on the well-being of children and families involved with the child welfare system (CWS). The survey examines child and family well-being outcomes in detail and seeks to relate those outcomes to experience with the CWS and to family characteristics, service needs and receipt, community environments, and other factors. To date, there have been three cohorts of NSCAW. The design of NSCAW III was guided by three priorities: (1) keeping NSCAW III as comparable to the two previous cohorts as possible, (2) minimizing response burden for all participants, and (3) updating the NSCAW III sample and instruments as needed to reflect the composition and characteristics of children being served by the CWS in 2017. NSCAW III includes 3,298 children ranging in age from 0 to 17.5 years old at the time of sampling. Children were sampled from child welfare investigations closed between July 2017 and September 2021. We provide information about methodological and operational challenges faced during the enrollment of NSCAW III (e.g., COVID-19 pandemic, state-level refusals) that required a new level of persistence and creativity, a pivot from past approaches, and the identification of solutions to maintain the integrity of this nationally representative study. [ABSTRACT FROM AUTHOR]