The NISMART studies were mandated by Congress to provide reliable national estimates of the number of children who became missing in the course of a year, and the proportion who were recovered. There were six major components to the NISMART study: (1) Random Digit Dial telephone survey; (2) Police Agency Records Study; (3) reanalysis of data from the Supplemental Homicide Reports of the FBI; (4) Returned Runaway Study; (5) Juvenile Residential Facility Study; and (6) supplementary analysis of selected data from the National Incidence Study of Child Abuse and Neglect. Five categories of missing child cases were developed: (1) family abductions; (2) non-family abductions; (3) thrownaways; (4) runaways; and (5) children who were lost, injured or missing for some other reason. The Returned Runaway Study was primarily a methodological study checking a possible limitation of the Random Digit Dial telephone survey of over 30,000 households. This report reviews the design and approach of the Returned Runaway Study; instrument development; training of interviewers; and data collection, coding, and processing. Tables, appendixes