Accurate measures of crime and costs contribute to assessing effectiveness of crime response programs. A paucity of data exists on criminal victimization of children and on the costs of such crimes. Prevalence rates refer to numbers of people who have experienced crime. But sometimes an individual is victimized repeatedly, as in the case of domestic violence and child abuse. Prevalence rates alone can underestimate crime occurrence and the severity of a crime's effect on and costs to an individual.
Incidence rates are counts of victimization, and therefore more accurately reflect amount of crime.
Ten rapes or beatings of a spouse are ten crime occurrences even though the victim is the same person. Earlier studies equated the number of victims with the number of crimes, underestimating the actual number of crimes and throwing off cost estimates accordingly. The present study focused on crime data from nationally representative surveys in which crime definitions were clearly reported. The cost of crime is typically underestimated due to problems in data collection. Specifically, NCVS excludes child abuse and neglect, drug abuse, murder, arson, drunk driving and crimes against children under 12.