The National Incidence Study (NIS) design assumes that the maltreated children who are investigated by child protective services (CPS) represent only the “tip of the iceberg.” Although the NIS estimates include children investigated by CPS, they also include maltreated children who are identified by professionals in a wide range of agencies in representative communities. These professionals, called “sentinels,” are asked to remain on the lookout for children they believe are maltreated during the study period. Children identified by sentinels and those whose alleged maltreatment is investigated by CPS during the same period are evaluated against standardized definitions of abuse and neglect. The data are unduplicated to ensure that a given child is counted only once in the study estimates.
The NIS-4 gathered data in a nationally representative sample of 122 counties selected to ensure the necessary mix of geographic regions and of urban and rural areas. The CPS agencies serving these counties were asked to provide data about all children in cases they accepted for investigation during one of two reference periods (September 4 through December 3, 2005 or February 4 through May 3, 2006). In addition, professionals working in the same counties in the following types of agencies were asked to serve as NIS-4 sentinels: elementary and secondary public schools; public health departments; public housing authorities; short-stay general and children’s hospitals; state, county and municipal police/sheriff departments; licensed day care centers; juvenile probation departments; voluntary social services and mental health agencies; and shelters for runaway and homeless youth shelters or victims of domestic violence.
The NIS-4 provided estimates of children whose maltreatment fit the study definitions. Two sets of definitions were used: the Harm Standard (which required the children to have been harmed by abuse or neglect) and the Endangerment Standard (which included harmed children but also included children who were endangered but not yet harmed by maltreatment). NIS estimated the number of children who experienced physical abuse, sexual abuse, emotional abuse, physical neglect, emotional neglect, educational neglect, any abuse, any neglect, and any maltreatment. The findings also indicated how many of the maltreated children had received CPS investigation.