The National Incidence Studies of Missing, Abducted, Runaway, and Thrownaway Children (NISMART) were undertaken in response to the mandate of the 1984 Missing Children's Assistance Act (Pub.L. 98-473) that requires the Office of Juvenile Justice and Delinquency Prevention (OJJDP) to conduct periodic national incidence studies to determine the actual number of children reported missing and the number of missing children who are recovered for a given year. The first such study, NISMART-1 (NATIONAL INCIDENCE STUDIES OF MISSING, ABDUCTED, RUNAWAY, AND THROWNAWAY CHILDREN (NISMART), 1988 [ICPSR 9682]), was conducted from 1988 to 1989 and addressed this mandate by defining major types of missing child episodes and estimating the number of children who experienced missing child episodes of each type in 1988. At that time, the lack of a standardized definition of a "missing child" made it impossible to provide a single estimate of missing children. As a result, one of the primary goals of NISMART-2 was to develop a standardized definition and provide unified estimates of the number of missing children in the United States. Both NISMART-1 and NISMART-2 comprise several component datasets designed to provide a comprehensive picture of the population of children who experienced qualifying episodes, with each component focusing on a different aspect of the missing child population. The Household Survey -- Youth Data and the Household Survey -- Adult Data (Parts 1-2) are similar but separate surveys, one administered to the adult primary caretaker of the children in the sampled household and the other to a randomly selected household youth aged 10 through 18 at the time of interview. The Juvenile Facilities Data on Runaways (Part 3) sought to estimate the number of runaways from juvenile residential facilities in order to supplement the household survey estimate of the number of runaways from households. And the Law Enforcement Study Data, by case perpetrator, and victim, (Parts 4-6) intended to estimate the number of children who were victims of stereotypical kidnappings and to obtain a sample of these cases for in-depth study.