Date of Award
Fall 2025
Project Type
Thesis
Program or Major
Justice Studies
Degree Name
Master of Arts
First Advisor
Donna Perkins
Second Advisor
Karen Van Gundy
Abstract
Sibling abuse is a common form of interfamilial abuse, but remains underreported, unrecognized, and is not researched as often as it should be (Yates et al., 2024). The purpose of the current study was to gain knowledge on sibling physical and sexual assaults according to the most recent available data from the 2023 National Incident-Based Reporting System (NIBRS). The data included information on victim and offender demographic characteristics (i.e., age, race/ethnicity, sex) as well as incident-level characteristics, which included relationship type between offender(s) and victim(s) (i.e., sibling or stepsibling), sex composition of offender and victim dyads, type of incident (i.e., physical or sexual assault), location of the incident, weapon use, and whether an injury was reported. Research questions aimed to answer what demographic characteristics of victims and offenders and what incident-level characteristics were most and least frequently present in sibling assault incidents overall, and which characteristics predicted the incident type (i.e., sibling physical and sibling sexual assault incidents) and the ratio of offenders to victims within incidents. Major findings regarding demographic differences in incident type (i.e., sibling physical vs. sexual assaults) and incident ratio of offenders to victims revealed some clear patterns. Overall, offenders tended to be male, and victims tended to be female. However, sibling physical assaults tended to have male offenders with both female and male victims almost equally, while male offenders were more likely and male victims less likely to be involved in sibling sexual assaults compared to sibling physical assaults. Analyses on the incident ratio of offenders to victims revealed that male offenders were less likely and male victims more likely to be involved in incidents with multiple offenders and/or victims. Findings regarding age indicated that sibling physical assaults involved older victims and offenders compared to sibling sexual assaults. Additionally, closer age gaps were found in sibling physical assaults compared to sibling sexual assaults. Interestingly, it was found that sibling physical assaults often involved adults, while sibling sexual assaults typically involved minors. Additional analyses on incident type found that older offenders and younger victims were more likely to be involved in sibling sexual assaults. Older offenders were also less likely to be involved in incidents with multiple offenders and/or victims. Regarding race and ethnicity, it appears that most reported incidents of both types involved families who identify as White, Black or African American, and Hispanic or Latino. Further analyses revealed that victims who identified as Black or African American, Asian, or Hispanic/Latino were less likely than White victims to be involved in reported sibling sexual assaults. Victims who identified as Black or African American were also less likely to be involved in incidents with multiple offenders and/or victims. A binary logistic regression revealed several incident-level characteristics that predicted incident type (i.e., sibling physical or sexual assault) after controlling for offender and victim demographic characteristics. Stepsiblings were 7 times as likely as siblings to be victims of sexual assault compared to physical assault. Also, incidents that occurred at the residence are almost 40% more likely to be sibling sexual assaults compared to sibling physical assaults. However, three incident-level characteristics decreased the likelihood that the incident types were sibling sexual assaults compared to sibling physical assaults, including incidents with weapon use (i.e., personal weapons 70% less likely; other weapon 80% less likely), injuries (i.e., minor injuries 93%; major injuries 35% less likely), and multiple offenders/victims (i.e., 34% less likely). Although weapon use and injury had lower frequencies in both sibling physical and sexual assaults, both were more likely to occur in sibling physical assaults compared to sibling sexual assaults. A second binary logistic regression analysis predicting the ratio of offender(s) to victim(s) (i.e., one offender/one victim; multiple offenders/multiple victims) also revealed interesting findings regarding incident-level characteristics after controlling offender and victim demographic characteristics. First, sibling sexual assaults were 37% less likely to involve multiple offenders and/or victims than one offender and one victim. Incidents occurring within the residence, or those in which either minor injuries or major injuries were reported were also less likely to involve multiple offenders and/or victims (7%, 9%, 11%, respectively ) compared to one offender and one victim. However, incidents that involved more traditional weapons (other weapons) were 37% more likely to involve multiple offenders and/or victims than one offender and one victim .
Recommended Citation
Mikuleza, Kayley Elizabeth, "Prevalence and Incident Characteristics of Sibling Physical and Sexual Assaults According to the 2023 National Incident-Based Reporting System" (2025). Master's Theses and Capstones. 2021.
https://scholars.unh.edu/thesis/2021