Patterning of Sexual Violence against Women across US Cities and Counties

Sexual violence against women is a global public health concern; yet, determining its patterning is still largely understudied. An excess of males has emerged as a central concern given that men are the primary perpetrators of violent behavior, particularly against women. However, it is increasingly unclear as to whether an excess or, rather, a shortage of men drives purported negative social outcomes. To address these conflicting expectations, we target data from the U.S. Census and the National Incident-Based Reporting System to explore the patterning of sexual violence against women across cities and counties in the United States. Through the use of generalized linear mixed models, we assess the role of adult sex ratio imbalance, along with measures of gender inequality, on sexual violence. Our results indicate mixed support for competing predictions. Violence does not simply increase by way of male surplus or shortage, but instead with increasing skew in the sex ratio. That is, balanced sex ratios exhibit the lowest rates of violence. However, rates of sexual violence against women increase more quickly with increasing male scarcity and are lowest at low levels of male excess (51%). Thus, our findings are particularly challenging to interpret from a ‘more males = more violence’ framework because violence increases more quickly with female excess and is rarest with a slight male bias in the population. We argue that these results highlight a need to target the specific types of violent behaviors expected to be motivated by partner availability, rather than overly simplistic predictions of male surfeit or deficit leading to an excess of violence.