Research Briefs

Factors Influencing Labeling Non-consensual Sex as Sexual Assault

Yndo & Zawacki, Journal of Interpersonal Violence, 2020

The authors’ study examined the effects of physical attractiveness and sexual interest cues on men’s sexual perceptions of women and whether increases in sexual perceptions of a woman would lead to decreases in labeling of subsequent non-consensual sex as sexual assault. The authors note that college age women are at high risk for sexual assault and that incidence of sexual assault among college aged women is high, ranging to as high as 50% in some studies, but men’s self-report perpetration averages are significantly lower than the number of  self-reported sexual assaults. The authors surmise this disparity may be partly due to the gendered difference in perception of what constitutes non-consensual sex.

Research has already identified men’s over perception of sexual interest, with males typically rating females participants as more attractive and more seductive and more sexually interested than females do. There is also limited research that suggests the level of a woman’s attractiveness influences the level of men’s misperception of sexual interest, perceiving more attractive women to be more interested in them, in a sense projecting their own sexual interest in the woman and assuming the woman’s level of interest is the same. The authors considered that men’s over perception may lead to misidentifying interested females and, coupled with ambiguous social cues from women that may or may not signal sexual attraction, may produce differing perceptions of actual sexual attraction, and the definition of the sexual activity, and may lead men to not perceive nonconsensual sex as sexual assault.

The authors examined two research questions in the study; What factors in a social interaction increase a man’s sexual perceptions of a woman, and do these increases in a man’s perceptions of a woman’s sexual interest during a social interaction decrease his labeling of subsequent nonconsensual sex as sexual assault? Their study contained 233 male college students who read a vignette describing a hypothetical social interaction between a man and a woman; within the vignette, the female character’s physical attractiveness (attractive vs. less attractive) and the degree to which the female character behaved interested in the male character (uninterested vs. ambiguous) were manipulated. The vignette ends with the male character physically forcing sexual intercourse with the female character. After reading the vignette, participants’ labeling of the nonconsensual sex as sexual assault was addressed. Participants’ perceptions of the female character’s sexual interest in the male character prior to the nonconsensual sex was assessed as a dependent variable during stopping points in the vignette, prior to sexual assault. The authors hypothesized that ambiguous cues (compared to non-interested) and more attractive female characters will result in the participants giving higher ratings of the female characters’ sexual interest in the males, as well as there being an interaction between level of female attractiveness and ambiguous cues, in that only with the ambiguous cues condition will female attractiveness work together to influence perceptions of sexual interest. The authors ultimately hypothesize that increased rating of the female character’s interest will lead to decreased labeling of the non-consensual sex in the vignette as sexual assault.

Utilizing multiple regression, their results indicated that separately, both ambiguous cues of interest and greater physical attractiveness had a significant effect on perceptions of the females character’s interest in the male character, though the interaction effect between the two variables was not significant. Consistent with previous research their results also indicated that  despite level of attractiveness, a lack of ambiguous cues and the presence of uninterested cues indicated the participants perceived a lower level of sexual interest from the female character, supporting that males can more easily distinguish sexual interest in the presence of clear cues and that cue ambiguity leaves more room for physical cues to influence perceptions. The second model also found that the level of perceived sexual interest had a significant effect on participants not labeling the non-consensual sex in the vignette as sexual assault.

While the effects are small, they are significant and having an understanding of the social factors that influence perceptions are important. The authors state that understanding the influence of social factors, such as physical attractiveness and interest cues, provides researchers with knowledge that can be incorporated into prevention programs targeted toward reducing sexual assault. For example, prevention programs should educate men that ambiguous sexual interest cues do not equate to consent. Furthermore, programs can increase awareness that perceptions of sexual interest may be inaccurate while highlighting the importance of gaining sexual consent, in turn encouraging unambiguous sexual consent between partners.

Yndo, M. C., & Zawacki, T. (2020). Factors influencing labeling nonconsensual sex as sexual assault. Journal of interpersonal violence, 35(7-8), 1803-1827.

While perceptions can affect whether non-consensual sex is viewed as a sexual assault, in instances where a sexual assault or domestic violence might be identified as such and witnessed, perception of the incidental factors, including the type of victim and type of assault, can influence whether bystanders intervene as Weitzman and colleagues discuss below.

Bystander Intervention on Behalf of Sexual Assault and Intimate Partner Violence Victims

Weitzman, Cowan, & Walsh, Journal of Interpersonal Violence, 2020

The authors utilized secondary data (data gathered in previous research) from a survey of individuals 15 years and older about bystander intervention and sexual assault and intimate partner violence (IPV). The authors note that  while sexual assault and IPV can co-occur–sexual assault can be a form of IPV and many victims experience both-from the vantage point of interveners, the two types of violence may be perceived quite differently. For instance, the authors note, the general public perceives the typical rape to be perpetrated by a stranger but often fails to perceive forced sex as rape if it occurs in the context of a romantic relationship. Even victims themselves often do not identify forced sex as rape if there is a romantic relationship between them and the perpetrator. Given that, definitionally, sexual assault and IPV are overlapping but distinct, and perceptions of these forms of violence are quite different, bystanders’ willingness to intervene and their strategies of intervention may differ. If these strategies do indeed differ by demographic background or violence type, then policies aimed at increasing bystander intervention would need to anticipate and accommodate these differences in order to be effective.

The authors had previously encountered limited research examining bystander intervention, finding that in the U.S. population at large, and among college students and military personnel specifically, men are more reluctant than women to intervene in instances of sexual assault. Among college students, men’s (but not women’s) willingness to intervene depends on their perceptions of the victim’s situation (e.g., whether they believe a victim increased his or her own risk of victimization) and research also suggests that Black college students are more likely to report intervening in sexual assault than Whites. Bystanders are also more likely to intervene in sexual assault and IPV if they perceive that victims face significant danger than if they don’t. Among college students, existing research finds a greater willingness to intervene on behalf of personally known sexual assault victims than on behalf of strangers, suggesting that this may be because knowing a victim encourages one to feel more responsible to act. College students also report a greater willingness to intervene on behalf of sexual assault victims when they feel supported by their peers, believe they know how to help, and are not in danger themselves. Thus, norms about intervention and education helping individuals to identify instances of sexual assault and IPV may also be critical to the decision to intervene.

The authors explain that once a person decides to intervene, a wide variety of strategies may be employed. These may include preventing violence by changing attitudes and beliefs that lead to assault or intervening in a potentially threatening situation before violence has begun; stopping violence mid-incident (which requires witnessing an event); or providing emotional or physical support after violence has occurred. All three types of interventions (before, during, and after) are theorized to reduce an individual’s subsequent risk of violence.

The dominant bystander intervention model, as stated by the authors, identifies five steps to the intervention process – noticing the situation (step 1), identifying it as an emergency (step 2), taking responsibility to act (step 3), deciding what specifically to do (step 4), and choosing to do it (step 5). According to the only nationally representative study of bystander interventions in IPV, only half of individuals who have known a victim have ever intervened and the authors conclude there are likely many barriers to intervening, at least in IPV, and these barriers may exist at every step.

For the current study, they examined three factors related to previous bystander experiences: whether the respondent has ever known a victim of sexual assault or IPV (separately); if yes, what the relationship was between the respondent and the victim and whether the respondent intervened; and if yes to the latter question, how the respondent intervened, including the relationship of the victim to bystander, type of intervention used, as well as possible barriers to a hypothetical IPV intervention with someone they knew. Demographics include race, age, gender, education, employment status, urban or non-urban status, and geographic region.

Significant differences lie in some demographics variables in the likelihood of knowing a victim of sexual assault and/or IPV as compared to not knowing one, with females more likely to know a victim, and more likely to know an IPV victim, specifically, than males, and Blacks being more likely than Whites to know a sexual assault victim. Significant differences were also found in the odds of knowing an IPV victim for those with some college, those who were students, retired individuals, and being an urban resident.

The authors state their findings show that part of the bystander intervention model (deciding what to do and choosing to do it) depends in part on the type of violence in question and gender. They found significant difference in the types of intervention used in sexual assault compared to IPV, with offering safe haven (47% compared to 60%) and telling the offender to stop (28% compared to 50%) used less frequently in sexual assault compared to IPV while telling the authorities or telling an adult were employed more frequently in IPV than in sexual assault. They also found significant differences in gender with regard to IPV, women are less likely to physically intervene than men, less likely to tell the abuser to stop, and more likely to tell an adult.

The main barriers to intervention in IPV in the current study were found to be that over 40% of respondents were concerned about being injured, while approximately 15% each, expressed concerns of it being a private matter, or being wrong for intervening. Other barriers, to a lesser degree, included losing friendship, being called a liar, and being bullied. This varied by demographic which showed age was a factor in concerns of being bullied and losing a friendship, while for females, risk injury was a greater concern than for men, however women were less likely than men to be concerned about it being a private matter or bullied which the authors surmise might occur because of their greater likelihood of knowing a victim of IPV. In regards to race, Blacks were more concerned about injury compared to Whites. For other demographics, those with post-secondary education were more likely to be concerned about being bullied over the intervention than those with less than a high school education. Full time workers were less likely to be concerned over the incident being a private matter whereas  urban residents were more likely to be concerned with it being a private matter than rural residents, Retired people were more likely to be inhibited with the possibility of being called a liar, and along with students, are more likely to have concerns about being wrong in intervening.

However, many of the respondents reported having intervening for victims of IPV (59%) and for sexual assault victims (29%). The authors analyzed whether the relationship in these instances influences whether an intervention occurs. Logistic regression analysis suggests that the odds of intervening in instances of sexual assault do not vary with relationship to the victim (e.g. whether they are a friend, family member, acquaintance etc.); however, they do differ with demographic background. Hispanic have 159% higher odds of intervening than White respondents (which the authors claim is a suggestion that certain cultural norms promote group welfare among Hispanic individuals). Self-employed respondents have 192% higher odds of intervening than non-employed respondents. However, in IPV, respondents have 70% lower odds of intervening on behalf of an acquaintance than on behalf of a family member. The author note that this finding coincides with previous research among college students, which suggests that individuals are more likely to intervene for friends than for strangers.

The authors conclude that the study indicates there are differences in the approaches individuals take when responding to sexual assault and IPV. They are more likely to involve legal authorities when responding to sexual assault, but more likely to tell the abuser to stop when responding to IPV. They state this finding indicates that some people may believe that sexual assault is a crime typically perpetrated by strangers that should be dealt with by legal authorities, whereas IPV is not a crime but a family issue best addressed by those close to or within the family. The authors believe to dispel these myths, public awareness campaigns should highlight that sexual assault more frequently occurs among individuals who know each other than among strangers, and should further provide specific suggestions for intervention strategies that do not put bystanders in immediate danger.

Weitzman, A., Cowan, S., & Walsh, K. (2020). Bystander interventions on behalf of sexual assault and intimate partner violence victims. Journal of interpersonal violence, 35(7-8), 1694-1718.

Reactions to, and treatment of, sexual assault and domestic violence victims will vary depending on the perceptions that both citizens and law enforcement have of these victims. Reactions to, and the treatment of, police officers are also subject to citizen perceptions, especially in regards to their perceptions of police legitimacy. However, Clark, et al explore whether these perceptions may vary by setting as they discuss in the following.

Differences in Citizen Perceptions of Interactions with Police Officers

Clark, Werling, Chintakrindi, & Randol, The Police Journal, 2019

The authors note the importance of police legitimacy in establishing trust with communities but recognize that a number of factors could affect the perception of legitimacy including race, age, income level, employment status, and education level as well as crime rates, nature and characteristics of an individual’s encounter with the police, media coverage of police activity, and police performance issues like excessive force, bias, and misconduct.

Because perceptions of the police are subjective, the authors looked at psychological perspectives that explain why or why not people defer to authority and find it legitimate. The authors state that two psychological models were found to influence whether a person defers to authorities and whether they see authorities as legitimate: an identity-based relational model, which had the biggest impact on views of legitimacy, and the resource-based instrumental model, which was found to play a smaller but still significant role in forming views on legitimacy. The relational model shows that people willingly defer to authorities, such as the police, and find them legitimate if people believe they are respected and valued by the authorities, are being treated in a neutral way, and can trust the motives behind how the authorities act; which are the same as the basis for the procedural justice concepts discussed at length by criminologist Tyler.

They note another psychological perspective that can help explain trust in the police is a Durkheimian perspective in that the most influential determinants of confidence and trust in the police were a sense of social cohesion and order in the community of the respondent. In a 2001 study, respondents also indicated they trust the police more when they perceive them as protecting moral structures in the community, not necessarily when they are protecting the community from crime. Likewise, fear of crime and signs of physical and social disorder did not have major impacts on citizens’ trust and confidence in the police, especially when controlling for social cohesion.

The authors state that most studies of police legitimacy involve large cities and little research has been done on midsize cities and conducted a survey in a central valley mid-sized California city and obtained 307 respondents. They stratified the sample from the different neighborhoods by police beat. The survey contained questions about how the city Police Department interacts with the community, the top three crimes respondents are concerned about, whether they feel safe in their neighborhood and how they perceive various aspects about the police officers in the city. They also asked a series of questions about the respondent’s contact with the police in the last 12 months and their satisfaction with those interactions. The authors sought to determine the perceptions of the respondents of their interactions with city police officers, utilizing police legitimacy outcome variables of fairness of police officers, trust of police officers, responsiveness to community concerns by police officers, and respectfulness of police officers. The authors utilized predictor variable that were likely to influence the outcome variables; race, household income level, education level, employment status, and crime rate.

In bivariate analyses, few of the predictor variables were correlated with the outcome variables measuring police legitimacy. There were no statistically significant differences between respondents’ perceptions of police respectfulness, and police responsiveness to the community based on race , household income level, education level, employment status, and crime rate. For the outcome variable of perceptions of police fairness, Blacks and American Indians held statistically significant lower views than other races but no other variable demonstrated any significant difference. For perceptions of trust of the police, the only significant difference was in employment status with  unemployed respondents having a significantly  higher trust in the police than employed respondents. The authors also used logistic regression models of the four outcome variables but the only statistically significant differences were in the perceptions of police fairness with White respondents being 2.18 times more likely to rate their interactions with police as being fair ‘A lot or to a great extent’ compared to Non-White respondents.

The author’s hypothesis that higher crime rates would negatively affect views of police legitimacy was not supported and there was only partial support that sociodemographic variables would show differences in views of police legitimacy. While their results differed from other research, the authors suggest the study might be more generalizable to medium sized cities, with more predominantly White populations rather than large cities. They conclude their results indicate “differences in people’s perceptions of interactions with the police are not something inherent within the people themselves or the crime in the areas they live, but something else. The most likely source in these differences in perceptions is something that the city police are doing, or potentially not doing, related to their face-to-face community interactions and training policies around communicating with local residents”. While noting some limitations to the study it suggests that future research can focus on small and medium sized cities, examine polices related to officer communication with the public, as well as explore other potential areas like media presentation that might affect views of police legitimacy.

Clark, N., Werling, R., Chintakrindi, S., & Randol, B. (2019). Differences in citizen perceptions of interactions with police officers. The Police Journal, 0032258X19826855.

Clark and colleagues examined how citizens perceived police officers’ trustworthiness, but how does the average citizen perceive the believability of a suspect’s alibi? Portnoy, et al state that innocent suspects who fail to provide a convincing alibi when interviewed by the police may subsequently be tried in court, where their alibi may be evaluated again by jurors. However, they question, are lay members of the public familiar with factors that may lead to an innocent suspect providing an inaccurate, incomplete or otherwise unconvincing alibi?

Beliefs about Suspect Alibis: A Survey of Lay People in the United Kingdom, Israel, and Sweden

Portnoy, Hope, Vrij, Ask, & Landström, The International Journal of Evidence & Proof, 2020.

The authors state that in general during an interrogation or interview, suspects will try to provide an alibi establishing their innocence, first through the recollection of the event and in a second more detailed phase designed to validate their story. However innocent suspects despite being motivated to provide an accurate and convincing alibi may provide inaccurate information. This may result from impaired memory processes, a result of a loss of details of an event over time, or memory conjunction errors, where suspects confuse aspects of two separate occurrences. However, the authors also consider that producing a convincing alibi may be hampered by a presumption of guilt from the interviewer. While the authors conceded that research to date hasn’t supported that presumptive guilt affects suspect’s willingness to deny or confess or that it affects the accuracy of the statements, they contend that presumptive guilt can lead to more aggressive interviewing, with research showing that it increases the probability of believing the suspect’s guilt despite their statements.

In evaluating suspects’ alibis for believability, police interviewers may not attribute inaccurate information to memory errors but rather to deception, and thus guilt. If a belief in their guilt is established, the suspect’s alibi may then be analyzed in court, by jurors, who will be unaware of factors that may have led to the suspect’s alibi as not believable and thus subject to prosecution. However without this understanding of the determinates of believability, jurors cannot make an informed decision.

The authors surveyed 332 people from the UK, Sweden, and Israel who had never provided an alibi in a police investigation to determine the degree in which lay people understood factors that affect believability. Participants were first asked to indicate their belief about the extent to which six types of details are provided in alibis of truthful versus lying suspects. Research has shown that alibis of liars and truth-tellers differ with respect to their tendency to provide these details and they wanted to examine how participants’ knowledge would align with these research findings. To gain additional data on participants’ beliefs about the differences between truthful and deceptive alibis, participants were then asked to describe what strategies they believed truthful and lying suspects typically use to make their alibi seem convincing to the interviewer.

They also asked participants what they believed the relation between the amount of details provided in an alibi and the truthfulness of the alibi to be, and to explain their answer. Since research has demonstrated that statements of truthful suspects are more detailed than those of lying suspects they were interested in the participants’ belief about the relation between alibis’ level of detail and their truthfulness.

Additionally, participants were also asked to indicate their belief regarding the extent to which truthful alibis might contain incorrect details to see whether or not participants would mention the factor of (impaired) memory processes. Participants who indicated that truthful alibis may contain incorrect details were asked to explain their answer in order to see if, and to what extent, they would acknowledge the factor of memory constraints as a reason for mistakes during the provision of alibis by truthful suspects.

The authors also examined the issue of presumption of guilt and first asked participants to indicate when they believed was the point in the course of an investigative interview in which interviewers begin to form their opinion regarding the suspect’s truthfulness. This question was used to examine whether or not participants would consider it likely that interviewers may conduct suspect interviews with a presumption of guilt toward the interviewee. This was followed by asking participants to indicate their belief regarding the extent to which a presumption of guilt held by interviewers at the beginning of suspect interviews might affect the interviewers’ behavior, and to indicate the likelihood that suspects provide more details and confess to committing the crime (regardless of their actual guilt) in response to a guilt-presumptive interviewer.

T-test analyses indicated that, on average, participants believed that most types of details are provided significantly more often in truthful than in deceptive alibis. In  response to common strategies, as two of the three most commonly reported strategies were reported for both truthful and lying suspects (i.e., providing detailed alibis and expressing confidence), they examined whether the proportion to which participants reported each of these two strategies differed for truthful and lying suspects. Analysis showed that participants believed that a detailed alibi occurs more often with respect to lying suspects (39.0%) than truthful suspects (26.6%). .In contrast, participants believed that expressing confidence occurs more often among truthful (30.0%) than lying suspects (16.6%).

Most participants who believed that a detailed alibi is less likely to be truthful explained that liars may believe that a detailed alibi is perceived as truthful and convincing. With respect to participants who believed that a detailed alibi is more likely to be truthful, most of them explained their belief by reporting that the truth is easy to keep track of and thus being informative is not difficult. Finally, most participants who believed that the amount of details provided in an alibi is not related to its truthfulness reported that the truthfulness of an alibi depends on different factors, such as the verifiability of the details provided, the extent to which the details provided are central to the main event, and the suspect’s personal strategy to appear truthful (which may or may not be to provide a detailed alibi).

In other areas of exploration, the study found, on average, participants rated the likelihood that a truthful alibi might contain incorrect details as relatively low. However, most participants who indicated they believed that truthful alibis may contain incorrect details explained that this may be due to impaired memory processes. Analyses also indicated that participants tended to believe significantly more often that interviewers usually begin to form their opinion of the guilt or innocence of suspects prior to hearing their alibi for the first time or while suspects are providing their alibi for the first time.

The study also found that, on average, participants believed that interviewers’ presumption of guilt can affect what interviewers say and how they behave during an interview. The most common explanation provided by participants who strongly believed this to be true was that presumptions of guilt make interviewers conduct harsher interviews, ask leading questions, and pressure the suspect to confess.,Finally, on average, participants believed that when suspects get the impression that the interviewer thinks they are guilty, they will provide more details in their alibi, and provide details even if they are uncertain of their accuracy.

The authors state the most noteworthy finding concerning participants’ beliefs about the qualities of suspect alibis was that participants believed that while truth-tellers are more informative with respect to specific types of details, liars more often try to appear generally informative. Specifically, participants tended to believe that, on average, setting, temporal, object, and person-description details are provided only slightly more often in alibis of truthful suspects than lying suspects. This belief aligns with existing research findings. However, when participants freely reported that suspects provide a generally detailed alibi to appear convincing, this was reported more often with respect to lying suspects than truthful suspects. Most participants also believed that the more details provided in an alibi, the less likely the alibi is to be truthful. Previous survey research has demonstrated similar beliefs of lay people about the relation between the amount of details provided by suspects during police interviews and suspects’ veracity.   Liars may succeed in providing a rich, detailed statement by describing an actual experience that occurred on a different time than that of the crime, with details concerning the crime nevertheless being denied or omitted. However, this belief of participants that a detailed alibi is less likely to be truthful contrasts findings in which statements of truthful suspects are usually more detailed than those of lying suspects.

The authors noted, however, impaired memory processes may prevent liars from remembering what information they have already provided (and to whom). In order not to struggle with remembering a detailed lie, liars are likely to provide a relatively short statement. Indeed, innocent, truthful suspects tend more than guilty, lying ones to employ an alibi-provision strategy of providing a detailed statement. Turning to the issue of impaired memory processes in the context of  innocent suspects’ alibis, participants’ responses indicated that they were reluctant to acknowledge that truthful alibis may unintentionally include incorrect details. This finding embodies another demonstration of lay people’s lack of understanding of issues concerning psychology and law and is consistent with previous findings that demonstrated this poor knowledge by lay people.

However, when examining the explanations of participants as to why they believed that truthful alibis may contain incorrect details, the authors state a more encouraging picture emerges. Participants acknowledged that impaired memory processes may prevent innocent suspects from reporting accurately from memory. For example, participants correctly acknowledged that innocent suspects may not encode relevant event details because of not realizing the importance of remembering the event for a later reporting. Participants also correctly mentioned that event details may be forgotten over time. Participants mentioned the factor of forgetting by truthful suspects also when explaining why they believed a detailed alibi may indicate that the suspect is lying (that is, because impaired memory processes may prevent innocent suspects from providing a detailed alibi).

The authors conclude that altogether, findings from the first part of the questionnaire suggest that participants hold some mistaken beliefs about suspect alibis. Nevertheless, participants did demonstrate an understanding that innocent suspects may provide incorrect details due to impaired memory processes. Results also suggest that lay people are aware of the fact that interviewers might approach suspect interviews while already presuming guilt and that this presumption of guilt might affect how interviewers conduct interviews. The findings also suggest that lay people believe that suspects’ verbal behavior is likely to be negatively affected by a guilt-presumptive interviewer.

The authors suggest future research might compare the beliefs of police interviewers with those of members of the general public about the topics of memory limitations and presumption of guilt in the context of suspect alibis. Specifically, jurors may benefit from being informed that innocent suspects may provide incorrect details due to memory constraints despite being motivated to be accurate. Jurors may also need to be explicitly informed that suspects sometimes provide their alibi to a guilt-presumptive interviewer; this should be done especially when suspects complain that their interviewer treated them as if they had already decided that they were guilty. These findings can also inform the development of interviewing techniques. For example, assuming that participants’ beliefs about the behavior of suspects reflect how they would behave as suspects during police interviews (as was also suggested by some responses), the finding that they believed that a more detailed statement is less likely to be truthful suggests that, as truth-tellers during police interviews, they would not try to provide a detailed statement. Accordingly, when interviewing suspects and instructing them to provide a detailed statement, it may be crucial to also explain to them the importance of being informative, for example, for the course of the investigation and the possibility of exonerating them as suspects by having more details to verify.

Portnoy, S., Hope, L., Vrij, A., Ask, K., & Landström, S. (2020). Beliefs about suspect alibis: A survey of lay people in the United Kingdom, Israel, and Sweden. The International Journal of Evidence & Proof, 24(1), 59-74.

Evidence Concerning the Regulation of Firearms Design, Sale, and Carrying on Fatal Mass Shootings in the United States

Webster, McCourt, Crifasi, Booty, & Stuart, Criminology and Public Policy, 2020

The authors (one affiliated with the Bloomberg Center for Gun Policy and Research) suggest that based on past research, the occurrence of mass shootings may be influenced by prohibited individuals, particularly domestic violence perpetrators (which they assert are disproportionately involved in mass shootings) and that while already prohibited from purchasing or possessing a firearm, prohibited individuals may purchase a firearm from someone other than a federally licensed dealer. The authors suggest that Comprehensive Background Checks (CBC), entailing a federal firearms background check on private transfers as well, may prevent some of these prohibited individuals from obtaining a firearm. They also suggest that purchaser licensing where states can tailor background checks, require gun safety courses, and give law enforcement officials discretion over whether a license is issued can be used to limit access to firearms, however the authors concede that there is no research to support that either CBC or purchasing licenses would reduce mass shootings. Indeed, in regards to other variables like assault weapon and large capacity magazine bans and their effect on mass shootings, other research has produced mixed results and contained methodological issues.

The authors used data from the FBI’s Supplemental Homicide Reports and other publicly available databases to calculate state-level annual incidence of 604 fatal mass shootings that had four or more victims between 1984–2017. The authors did note that the SHR did not contain some prominent mass shootings such as the Aurora, CO theater , Sandy Hook  elementary school, and the church in Southerland Springs, TX. The also note that because the SHR limits the number of victims to 11, the Virginia Tech shooting in their data is counted as three incidents. To remedy these and other omissions, they compared the SHR data with data on mass shootings collected by Stanford University (Stanford Mass Shootings in America) for the years 1984–2017 and the Gun Violence Archive for the years 2014–2017 and added any missing incidents to their data set.

Data on gun laws were collected and coded and included a number of state-level statutes: concealed carry laws, handgun purchaser licensing laws that require either in-person application or fingerprinting, laws requiring point-of-sale background checks only, firearm prohibitions for subjects of domestic violence restraining orders that include ex parte orders, firearm prohibitions for subjects of domestic violence restraining orders that include dating partners in the definition of domestic violence, firearm prohibitions for subjects of domestic violence restraining order that do not include ex parte orders or dating partners, laws requiring surrender of  all firearms by subjects of domestic violence restraining orders, firearm prohibitions for violent misdemeanants, assault weapons bans and large capacity magazine bans.

Negative binomial regression models were used to estimate the associations between changes in key gun laws and fatal mass shootings. Analyzed at the state-year level,  they conducted a time series analysis of three dependent variables; domestic violence linked mass shootings, which the authors (with the authors defining domestic relationship broadly to include any offender-victim family relationship, boyfriend/girlfriend, or ex-spouse), non-domestic violence linked mass shootings  (however the SHR defines the offender-victim relationship based on the first  homicide in the incident) and all mass shootings.

Analyses of the statistical models indicated that some of the variables had an effect on the outcomes measures. For total number of mass shootings incidents only two law variables had a statistically significant effect; states that had handgun purchaser licensing laws requiring in-person application with law enforcement or fingerprinting were associated with incidents of fatal mass shootings 56% lower than that of other states and LCM bans indicated a 48% lower risk of fatal mass shootings associated with the policy. They found no evidence that concealed carry laws, assault weapons bans, prohibitions for domestic abusers and violent misdemeanants, or point-of-sale CBC laws were associated with the incidence of fatal mass shootings. In models in which the number of mass shooting victim fatalities was the outcome, statistically significant protective effect variables included handgun purchaser licensing (66% reduction) as well as LCM bans (70% reduction) which, however, also demonstrated a wide confidence interval that calls into question its true effect.

For models examining non-domestic violence related incidents, purchaser licensing was shown to have a significant negative effect on both the number of incidents (62% reduction) and in the number of victims (65% reduction) in these incidents compared to other states. For models examining domestic violence incidents (28% of the sample) only LCM ban laws had a significant reduction effect on the number of incidents (61%) and the number of victims (75%) but states with required comprehensive background checks were associated with a large significant increase (222%) in victim deaths in these incidents.

The authors concede that the findings of this study suggest that the most common policy prescriptions and criticisms offered by gun control advocates-comprehensive background checks, assault weapons bans and “Right to Carry” laws which reduce restrictions on civilian concealed carry-do not seem to be associated with the incidence of fatal mass shootings. Despite the authors attempting to tie domestic violence to mass shootings, with 28% of  the shootings in this study having some connection to domestic violence, they found no evidence that laws designed to keep firearms from perpetrators of domestic violence have affected mass shootings connected to domestic violence. They state this is surprising given that prior research demonstrating that laws prohibiting persons under domestic violence restraining orders from possessing firearms or with prior convictions for violent misdemeanors were associated with reduced intimate partner homicides. The authors conclude their findings suggest that laws requiring firearm purchasers to be licensed through a background check process supported by fingerprints and laws banning LCMs are the most effective gun policies for reducing fatal mass shootings.

Webster, D. W., McCourt, A. D., Crifasi, C. K., Booty, M. D., & Stuart, E. A. (2020). Evidence concerning the regulation of firearms design, sale, and carrying on fatal mass shootings in the United States. Criminology & Public Policy, 19(1), 171-212.

As noted above, different databases may define mass violence offenses differently and that beside the common feature of having multiple victims there is no universal definition of these events, which can make researching these events more challenging. Without clear definitions of mass violence, research and its implications and conclusions can be unclear or forward incomplete or inaccurate policy recommendations. Corzine and Corzine and explore the differences in definitions and subtypes, issues in research, and recommendations for future research.

 The Devil’s In the Details: Measuring Mass Violence

Corzine and Corzine, Criminology and Public Policy, 2020

The authors note that within mass violence incidents, as measured by different sources and databases, major characteristic differences exist. For example the definition of an occurrence as a mass violence event may vary on the minimum number of victim (either 3 or 4 killed, sometimes including the wounded), location (some require a public location while others include residential and private locations), timing (some require them to have occurred within a 24 hour period), and whether a firearm was used. Defining other general characteristics of these events, and research into them, is made more difficult by specific variations in the incidents. For example, age of the typical victim can vary depending on the type of target, an event occurring at a school will have on average younger aged victims than a church. Events may occur based more on the location, rather than on specific individualized targets, and the offender-victim relationships may vary widely or be unknown, just as the motives may vary widely or be unknown.

The authors consider the FBI’s definition of two types of mass violence; a Classic type and a Family type. A killing of at least three family members is defined as a mass murder, or if involving a perpetrator suicide, a mass murder /suicide. If the perpetrator lives and kills four or more family members it’s described as a Family Killing, rather than a mass murder. A Classic type involves a single perpetrator (usually a mentally disordered male) who kills four or more victims in a public place with no cooldown period. These events can also be defined as mass violence victimization, in that while the two previously described types of mass killings will typically vary by location (public or private) victim type, motive, and even weapon use, both with result in physical injury, death, and emotional and psychological trauma for survivors.

However, the authors recognize that events described as public mass murders or mass shootings typically have garnered the most media and research attention with data collections efforts from various official government entities, although with some variation. The Office of Crime Victims (OCV) which has a focus on the toll on crime victims, utilizes data collected from the Mother Jones news organization. The OCV defines mass violence as an intentional violent criminal act, for which a formal investigation has been opened by the FBI or other law enforcement agency, that results in physical, emotional, or psychological injury to a sufficiently large number of people to significantly increase the burden of victim assistance and compensation for the responding jurisdiction. OCV provides general information to program news, training for providers and community leaders, through grants and funding, and in links to numerous fact sheets and articles on victimization.

The FBI’s definition of mass murder consists of four or more victim deaths (not counting the offender) in one or more locations in a close proximity by the offender, is the definition typically adhered to by other official organizations, though the number of qualifying victims was later reduced to three in 2013 by presidential mandate. In contrast, the Congressional Research Service (CRS)  focuses on gun-related mass violence of all types, defining “mass shooting” as a “multiple homicide incident in which four or more victims are murdered with firearms, within one event, and in one or more locations in close proximity”. Mass shootings were broken down by type rather than exclusively by number, and categorized mass murders with firearms as either mass public shootings, familicides, and other mass shootings. These categories demonstrate a shift from analysis based solely on numbers of murdered or injured to one examining the type of event, which the authors contend holds promise for future research in not just describing the events but understanding them.

There are also a number of publicly available and unofficial data sources. These include the Gun Violence Archive, collecting data since 2012, which defined mass violence as four or more shot or killed (this expands the definition to included wounded) in one location, over a short time frame. It obtains its data from the media, law enforcement, and government sources, and their data is also used by the Guardian news organization for their reporting and data collection on mass shootings. Mother Jones’ data, the primary data source for the OCV, started in 1982 collecting data on mass shootings that followed the FBI’s definition of four victims (later three) of “indiscriminate rampages” in public places. Gang violence, armed robbery, and other felony-related events that generated several gun-related deaths are excluded from the data set. The Washington Post in 1966 began collecting data on mass violence, with a focus on firearms used to kill or injure four or more victims, through its own researchers making it a good resource for examining trends in mass violence. Since 2013, Mass Shooting Tracker relies on what they call a “crowd-sourced database.” Volunteers from around the United States report into the main hub where the shootings are recorded. A “mass shooting” is defined as a single “outburst” of violence in which four or more people are killed and/or injured. There is at least one link to a news article from the city where the shooting took place.

From this it can seen that there is variation amongst the most common measures of mass violence including how they are measure, varying between three and four victims and some including only deaths while some include injuries and deaths, with most of the publicly available source focus on incidents involving firearms versus other weapons.

The authors also notes the availability of datasets that are related to but not directly measuring mass violence like the FBI’s and the NYPD’s respective active shooter database tracking incidents of active shooters, primarily for developing evidence based responses to active shooter incidents. Some organizations track all firearm related deaths and injuries in support of laws that restrict gun ownership like Everytown for Gun safety, which primarily utilizes CDC data and sets a threshold of four or more fatalities (excluding the perpetrator) for mass murder or the Brady Campaign and Center, an organization that got its start in the mid 70’s as a gun control group. It collect’s data on firearm injuries and deaths and has developed  a comprehensive plan of strict gun regulation.

Other more detailed sources of data exist in the form of the Supplemental Homicide Reports (SHR) from the FBI, which adds another layer of details to the UCR’s homicide data. While information is provided about victim and offender numbers and demographics, their relationship, the circumstances, and weapons used however it doesn’t denote the location and other additional circumstances around the incident. The National Incident Based Report System (NIBRS) is a much more detailed crime reporting system than the UCR (and SHR), which it was set to replace in 2021, however less than half of law enforcement agencies are participating. Corzine and Corzine state that overall NIBRS will offer significant improvements over the UCR. All of the crimes people are arrested for will be in NIBRS rather than the one most serious crime a suspect is charged with, as is currently recorded in the UCR. NIBRS collects more detailed information on 52 crimes plus ten offenses for which only arrest data are known. By covering all of the crimes that a person committed during an incident of mass violence or with which he or she is being charged, much more is known about the event than can be found using the SHR.

The large number of incident variables which include things like location codes, time of day, and whether the incident as cleared by arrest provides much more detailed data, which is more conducive to statistical analysis research on mass violence incidents. The authors note that none of the official definitions of mass violence or its subtypes to date focus on family mass murders, but state there needs to be more attention given to the private or family type of mass violence, and this data set will allow for the study of 2 or more victims in public and private settings. Even using the more restrictive definition of four fatalities, these comprise approximately half of the mass murder events in the parts of the United States covered by NIBRS.

As the authors illustrated, differences in data sources of mass violence can provide different descriptive results, depending on if a mass shooting is defined by, and it number of victims derived from, different sources as some data include both dead and wounded in victim totals, while some only count the deceased, with starting points that could vary between three and four victims depending on the year the data was obtained. The availability of  particular aspects of mass violence is also dependent on the source as some data sets lack important information like victim-offender relationship and location or setting and while public mass shootings have garnered a lot of attention, private setting or family mass murders provide another important avenue of research into mass violence. In particular the authors outline some implications and challenges for future research:

• One of the first things that must be done is to separate the various types of mass violence, so we can examine the uniqueness of each one.

• We need to study mass murder that occurs in public places and private places.

• We need to study the foiled cases.

• We need to understand how the role of mental health, or the lack thereof, is associated with mass killing.

• We need to explore who offenders choose as their targets and how they do so.

• We need to explore the influence that the hatred of certain groups has on the choice of who and where to target victims.

• We need to understand the role that loss plays in motivation, including the loss of a job, the loss of a loved one through divorce or death, and the loss of being viewed with respect.

The authors state that from a measurement standpoint, the data set that would best satisfy researchers’ needs will include the following:

• Two or more victims per private/family event who have been killed

• Three or more victims per public mass violence event who have been killed

• Any three or four injured persons occurring during the same incident

• Any history of an offender’s mental illness, a criminal record, or domestic violence

• All weapon(s) used to injure and/or kill victims

Having this information will generate more detailed, nuanced data that will allow law enforcement and researchers a better understanding of the circumstance around these events, distinguishing between subtypes of these events, how they might be prevented more often.

Huff‐Corzine, L., & Corzine, J. (2020). The devil’s in the details: Measuring mass violence. Criminology & Public Policy, 19(1), 317-333.

Author: Frank Heley

Frank Heley graduated from North Dakota State University with a BS in Criminal Justice in 2009, a MS in Criminal Justice Administration in 2012, and a PhD in Criminal Justice, with a focus on policing, in 2018, and is a current member of the Academy of Criminal Justice Sciences. He has worked as a security supervisor in the hospitality field, as a drug and alcohol researcher, and as a criminal justice instructor, as well as having been a private investigator for 21 years. Under the auspice of the Center for Criminological Inquiry, he currently conducts independent research and provides consulting services.