The NIS-3 offers an important perspective on the scope of child abuse and neglect. The NIS includes children who were investigated by child protective service (CPS) agencies, but it also obtains data on children seen by community professionals who were not reported to CPS or who were screened out by CPS without investigation. This means that the NIS estimates provide a more comprehensive measure of the scope of child abuse and neglect known to community professionals, including both abused and neglected children who are in the official statistics and those who are not. The NIS follows a nationally representative design, which means that the estimates represent the numbers of abused and neglected children in the United States who come to the attention of community professionals.

The NIS-3 was conducted in a nationally representative sample of 42 counties. In every county, the CPS agency was a key participant, providing basic demographic data on all the children who were reported and accepted for investigation during the 3-month study data period, September 5 through December 4, 1993. Further details about the child's maltreatment and the outcome of the CPS investigation were obtained for a representative sample of these cases.