The study includes 5,873 children ranging in age from birth to 17.5 years old at the time of sampling. Children were sampled from child welfare investigations closed between February 2008 and April 2009 in 83 counties nationwide. The cohort includes substantiated and unsubstantiated investigations of abuse or neglect, as well as children and families who were and were not receiving services. Infants and children in out-of-home placement were oversampled to ensure adequate representation of high-risk groups. Face-to-face interviews or assessments were conducted with children, parents and nonparent adult caregivers (e.g., foster parents, kin caregivers, group home caregivers), and investigative caseworkers. Baseline data collection began in March 2008 and was completed in September 2009. Additional information about the
NSCAW II history, sample design and methods, instrumentation, as well as a summary of differences between the NSCAW I and NSCAW II cohorts can be found in the first report, Introduction of this NSCAW II Baseline series.