The National Violence Against Women Survey (NVAWS) categorized perpetrators and reported incidents with a survey design biasing upward intimate partner violence and domestic violence as shares of reported violence. The frequency of victimization incident reports depended on the perpetrator categorization scheme. NVAWS included 28 perpetrator categories associated with intimate partner violence, 47 categories associated with domestic violence, 2 categories for violence by friends and acquaintances, and 3 categories for violence by strangers. NVAWS collected perpetrator-incident reports for incidents in perpetrator categories. The maximum number of perpetrator categories reported by men and women was six and five, respectively. If a respondent reported being physically assaulted by more than one perpetrator in a perpetrator category, only “the most recent of these offenders” was reported in detail.^ Hence a respondent could report in detail at most three physical assault by strangers, but up to 47 physical assaults by different categories of domestic violence perpetrators. This survey design biased upward intimate partner violence and domestic violence as shares of violent incidents reported in detail.

NVAWS reporting of multiple perpetrator incidents probably increased its categorization bias. NVAWS included only one multiple perpetrator category: “male & female stranger.” No incidents were coded for this perpetrator category among victimizations of men, and only five instances were coded for this perpetrator category among victimizations of women. The National Crime Victimization Survey (NCVS), in contrast, reported 8% and 4% of victimization incidents of men and women, respectively, as having been by more than one perpetrator. Multiple-perpetrator incidents in NVAWS seem to have been reported as separate incidents for each perpetrator. Such reporting magnified the NVAWS perpetrator-category coding bias.

In addition to biased categorization of violence perpetrators, NVAWS has other major weaknesses. The U.S. National Electronic Injury Surveillance System All-Injury Program (NEISS AIP) provides much better quality national estimates of serious incidents of domestic violence than does NVAWS.