Disaggregating Mass Public Shootings: A Comparative Analysis of Disgruntled Employee, School, Ideologically motivated, and Rampage Shooters

Comparison of rampage and non-rampage mass shootings in the U.S.: A 5-year demographic analysis

BACKGROUND

Rampage mass shootings (RMS) are a subset of mass shootings occurring in public involving random victims. Due to rarity, RMS are not well-characterized. We aimed to compare RMS and NRMS. We hypothesized that RMS and NRMS would be significantly different with respect to time/season, location, demographics, victim number/fatality rate, victims being law enforcement, and firearm characteristics.

STUDY DESIGN

Mass shootings (4 or more victims shot at a single event) from 2014-2018 were identified in the Gun Violence Archive (GVA). Data were collected from the public domain (e.g. news). Crude comparisons between NRMS and RMS were performed using Chi-squared or Fisher's exact tests. Parametric models of victim and perpetrator characteristics were conducted at the event level using negative binomial regression and logistic regression.

RESULTS

There were 46 RMS and 1626 NRMS. RMS occurred most in businesses (43.5%), whereas NRMS occurred most in streets (41.1%), homes (28.6%), and bars (17.9%). RMS were more likely to occur between 6AM-6PM (OR=9.0 (4.8-16.8)). RMS had more victims per incident (23.6 vs. 4.9, RR: 4.8 (4.3,5.4)). Casualties of RMS were more likely to die (29.7% vs. 19.9%, OR: 1.7 (1.5,2.0)). RMS were more likely to have at least one police casualty (30.4% versus 1.8%, OR: 24.1 (11.6,49.9)) or police death (10.9% versus 0.6%, OR: 19.7 (6.4,60.3)). RMS had significantly greater odds that casualties were adult (OR: 1.3 (1.0,1.6)) and female (OR: 1.7 (1.4,2.1)). Deaths in RMS were more likely to be female (OR: 2.0 (1.5,2.5)) and White (OR: 8.6 (6.2,12.0) and less likely to be children (OR: 0.4 (0.2,0.8)). Perpetrators of RMS were more likely to die by suicide (34.8%), be killed by police (28.3%), or be arrested at the scene (26.1%), while more than half of perpetrators from NRMS escaped without death or apprehension (55.8%). Parametric models of perpetrator demographics indicated significant increases in the odds that a RMS shooter was White (OR: 13.9 (7.3,26.6)) or Asian (OR: 16.9 (3.7,78.4)). There was no significant difference in weapon type used (p=0.35).

CONCLUSION

The demographics, temporality, and location differ between RMS and NRMS, suggesting that they are dissimilar and require different preventive approaches.

Fame through surprise: How fame-seeking mass shooters diversify their attacks

Mass shootings are becoming more frequent in the United States, as we routinely learn from the media about attempts that have been prevented or tragedies that destroyed entire communities. To date, there has been limited understanding of the modus operandi of mass shooters, especially those who seek fame through their attacks. Here, we explore whether the attacks of these fame-seeking mass shooters were more surprising than those of others and clarify the link between fame and surprise in mass shootings. We assembled a dataset of 189 mass shootings from 1966 to 2021, integrating data from multiple sources. We categorized the incidents in terms of the targeted population and shooting location. We measured "surprisal" (often known as "Shannon information content") with respect to these features, and we scored fame from Wikipedia traffic data-a commonly used metric of fame. Surprisal was significantly higher for fame-seeking mass shooters than non-fame-seeking ones. We also registered a significant positive correlation between fame and surprisal controlling for the number of casualties and injured victims. Not only do we uncover a link between fame-seeking behavior and surprise in the attacks but also we demonstrate an association between the fame of a mass shooting and its surprise.

From violent lone-actor types to lone-actor grievance-fueled violence: The Aarhus University shooting as an example of multi-facetted offender motivations and context-sensitive boundaries between violent lone-actor categories

Over the last decade, western societies have experienced an increase in acts of mass violence carried out by lone actors. While this concept is mostly associated with lone-actor terrorists, it also involves the actions of other single perpetrators, e.g., school shooters, workplace attackers, rampage shooters, and some forms of incel violence. In this article, we argue in favor of moving away from such categorization of violent lone-actor types and toward the unifying concept of lone-actor grievance-fueled violence. We illustrate the analytical benefits gained from such a conceptual shift by analyzing the Danish Aarhus University Shooting in 1994, where a single offender killed two students. While this attack is widely accepted as the only Danish school shooting in history, we identify signs of an extremist misogynist worldview held by what we today would call incels. This case serves as an illustration of the blurred and context-sensitive boundaries between violent lone-actor types and how nuances in offender motivation can be lost when lone-actor attacks are classified within a typological framework. Rather than simply recasting the Aarhus University Shooting as an incel attack considering the recent development of this category, we argue for the need to embrace the conceptualization of lone-actor grievance-fueled violence, which points toward the common genesis of lone-actor violence and allows for multi-faceted offender motivations. Using the Aarhus University shooting as a steppingstone, we discuss the pitfalls of lone-actor violence typologies and the advantages of the unifying lone-actor grievance-fueled violence conceptualization for both academia and practice.

Mental disorder, psychological problems and terrorist behaviour: A systematic review and meta-analysis

Background

The link between mental health difficulties and terrorist behaviour has been the subject of debate for the last 50 years. Studies that report prevalence rates of mental health difficulties in terrorist samples or compare rates for those involved and not involved in terrorism, can inform this debate and the work of those responsible for countering violent extremism.

Objectives

To synthesise the prevalence rates of mental health difficulties in terrorist samples (Objective 1-Prevalence) and prevalence of mental health disorders pre-dating involvement in terrorism (Objective 2-Temporality). The review also synthesises the extent to which mental health difficulties are associated with terrorist involvement compared to non-terrorist samples (Objective 3-Risk Factor).

Search Methods

Searches were conducted between April and June 2022, capturing research until December 2021. We contacted expert networks, hand-searched specialist journals, harvested records from published reviews, and examined references lists for included papers to identify additional studies.

Selection Criteria

Studies needed to empirically examine mental health difficulties and terrorism. To be included under Objective 1 (Prevalence) and Objective 2 (Temporality), studies had to adopt cross-sectional, cohort, or case-control design and report prevalence rates of mental health difficulties in terrorist samples, with studies under Objective 2 also needing to report prevalence of difficulties before detection or involvement in terrorism. For Objective 3 (Risk Factor) studies where there was variability in terrorist behaviour (involved vs. not involved) were included.

Data Collection and Analysis

Captured records were screened in DisillterSR by two authors. Risk of bias was assessed using Joanna Briggs Institute checklists, and random-effects meta-analysis conducted in Comprehensive Meta-Analysis software.

Results

Fifty-six papers reporting on 73 different terrorist samples (i.e., studies) (n = 13,648) were identified. All were eligible for Objective 1. Of the 73 studies, 10 were eligible for Objective 2 (Temporality) and nine were eligible for Objective 3 (Risk Factor). For Objective 1, the life-time prevalence rate of diagnosed mental disorder in terrorist samples (k = 18) was 17.4% [95% confidence interval (CI) = 11.1%-26.3%]. When collapsing all studies reporting psychological problems, disorder, and suspected disorder into one meta-analyses (k = 37), the pooled prevalence rate was 25.5% (95% CI = 20.2%-31.6%). When isolating studies reporting data for any mental health difficulty that emerged before either engagement in terrorism or detection for terrorist offences (Objective 2: Temporality), the life-time prevalence rate was 27.8% (95% CI = 20.9%-35.9%). For Objective 3 (Risk Factor), it was not appropriate to calculate a pooled effect size due the differences in comparison samples. Odds ratios for these studies ranged from 0.68 (95% CI = 0.38-1.22) to 3.13 (95% CI = 1.87-5.23). All studies were assessed as having high-risk of bias which, in part, reflects challenges conducting terrorism research.

Author's Conclusions

This review does not support the assertion that terrorist samples are characterised by higher rates of mental health difficulties than would be expected in the general population. Findings have implications for future research in terms of design and reporting. There are also implications for practice with regards the inclusion of mental health difficulties as indicators of risk.

US Mass public shootings since Columbine: victims per incident by race and ethnicity of the perpetrator

White individuals in the United States (US) have historically had disproportionate access to firearms. The real-life availability of firearms, including those most lethal, may still be greater among White populations, manifesting in the number of victims in shootings. We compared the severity of US mass public shootings since Columbine by race and/or ethnicity of the perpetrator using The Violence Project Database of Mass Shooters, assessing fatalities (minimum four), total victims, type, and legal status of guns used. We used data visualization and Quasi-Poisson regression of victims minus four - accounting for truncation at 4 fatalities - to assess fatality and total victim rates comparing Non-Hispanic (NH) White with NH Black shooters, using winsorization to account for outlier bias from the 2017 Las Vegas shooting. In 104 total mass public shootings until summer 2021, NH White shooters had higher median fatalities (6 [IQR 5-9] versus 5 [IQR 4-6]) and total victims (9 [IQR 6-19] versus 7 [IQR 5-12]) per incident. Confidence intervals of NH Black versus NH White fatalities rate ratios (RR) ranged from 0.17-1.15, and of total victim RRs from 0.15-1.04. White shooters were overrepresented in mass public shootings with the most victims, typically involving legally owned assault rifles. To better understand the consequences when firearms are readily available, including assault rifles, we need a database of all US gun violence. Our assessment of total victims beyond fatalities emphasizes the large number of US gun violence survivors and the need to understand their experiences to capture the full impact of gun violence.

Guns on campus: An autoethnography of “concealed carry” policies

In the United States, school shootings are a common social problem and frequently occur on both K-12 and college campuses. High profile school shootings have resulted in a growing number of state governments legalizing “concealed carry” on college campuses, increasing the presence of guns in classrooms. This research study employs qualitative autoethnography to present the author's experiences teaching on a campus where concealed carry was implemented in 2014. Through autoethnographic narratives, the author describes her lived experiences. This paper analyses these narratives using intersectional feminist theory and situates the narratives within the broader socio-cultural context of gun culture in the Pacific Northwestern USA. The author spent four years immersed in the culture of concealed carry, and has written multiple narratives detailing these experiences. Two narratives are presented in this work. Important findings in this work include examinations of: how the presence of guns in college classrooms shapes power dynamics; the use of fear-based curricula in active-shooter survival trainings; the cultural construction of the “good guy with a gun”; and the implications of the author's positionalities within gun culture. This research study encourages the reader to engage with and learn from the lived experiences of the author.

Mass violence planned as ultimate leisure experience? Four diverse cases

As part of a larger project on contextual factors of mass murder, this paper identifies and discusses four cases that quite clearly suggest, based on the content of perpetrators' personal communications and/or reports from those who knew them, that the perpetrators purposely planned and experienced their attacks as desired leisure experience. Leisure science, while consistent with the multidisciplinary roots of forensic behavioral science, has not yet been applied to better understand cases of mass violence. Together with traditional forensic behavioral science approaches, leisure theory may produce insights in cases of mass violence that are uncoerced, largely intrinsically motivated, and committed for personal enjoyment.

Gender-Based Mass Shootings: An Examination of Attacks Motivated by Grievances Against Women

This study provides a quantitative examination of gender-based mass shootings in America from 1966-2018. Gender-based mass shootings refer to attacks motivated by grievances against women, divided into four categories based on a specific woman or women in general, as well as whether they directly target the source of their grievances. Findings indicate that specific woman-targeted shooters were the most common and significantly different from their counterparts in their domestic violence history, racial diversity, and engagement in spree attacks. When comparing all gender-based attacks against other mass shootings, significant differences include relationship status, children, domestic violence history, substance abuse history, and suicide. This investigation provides implications for gender and mass shooting scholars, as well as practitioners developing strategies for intervention and prevention.

Operational research applied in the field of public security

Purpose

Because that the crime in a wide way impacts the life of the people in the big metropolis, researchers have treated the question from several angles. The purpose of the paper, under the umbrella of operational research, is to develop a model of the ordering of police strategies, in the fight against crime in general, according to a certain criminal demand.

Design/methodology/approach

For the construction of the impact matrix of the strategies under the reduction of crime rates, considering a portfolio of crimes, a questionnaire applied to specialists was used. In a second moment, defined the criteria and strategies to be ordered, the multicriteria ELECTRE IV method was used, which with the help of the J-Electre software emulated the systematized data in the impact matrix and produced the final ordering of the most efficient strategies, in the fight against crime, in the perception of decision-makers.

Findings

As a result, the research revealed that policing strategies directed at solving specific crimes are the most effective in the perception of decision-makers after the emulation of data with the ELECTRE IV method.

Research limitations/implications

As research implications, it can be inferred that the use of multicriteria methods in the modeling of problems in the area of public security can contribute to rationalization of the use of the means available in the fight against crime in large cities. The research showed that it is possible to use customized policing strategies to a certain reality.

Practical implications

The method presented in this research is directly related to the major strategies: problem-oriented policing and hot spot policing. This method allows public safety managers to consider the possibility of combining different law enforcement strategies in each context. In this sense, the use of the multiple-criteria decision analysis (MCDA) (ELECTRE IV) method allows the evaluation of a large set of alternatives according to a set of established criteria, speeding up the process and reducing subjectivity, allowing the manager to analyze several scenarios with greater clarity and impartiality and choosing an alternative that best solves the proposed problem. The expected result is the rationalization of the available means applied in the search for the reduction of crime rates.

Social implications

The customization of policing strategies, according to criminal demands, implies the efficient way to reduce criminal charges. Reducing criminal rates enables the development of the local economy, tourism and the quality of life of people by exercising their freedom to the full.

Originality/value

The originality lies in filling a gap in the literature with the elaboration of the impact matrix of policing strategies in reducing criminal indices, and in their associated use in ordering strategies through a multicriteria method.

Psychometric Properties and Development of a Scale Designed to Evaluate the Potential of Predatory Violent Behavior

The objective of this study was to develop and determine the psychometric properties of an instrument designed to detect traits and behavior that are associated with predatory violent behavior, which is defined as a determined, planned, controlled, and proactive aggression. The sample was comprised of 564 students, mostly in their last year of high school, or in their first year of college. The initial instrument had 78 items, ultimately resulting in 13 with good internal consistency (α = 0.825). Factor analysis showed four factors: anger-in, appeal for weapons, suicidal ideation, and the tendency to take justice into one’s own hands. Said factors showed significant correlations of convergent validity. Data shown here allows inferring that the instrument is a novel and concise tool that evaluates and detects the potential of predatory violent behavior.