Lethality of Civilian Active Shooter Incidents With and Without Semiautomatic Rifles in the United States

Abstract

Semiautomatic rifles have been used in some of the largest active shooter incidents in US history. 1 The weapons were banned in 1994 under the federal assault weapons ban but were reintroduced to the public marketplace in 2004. 2 Currently, there are no comprehensive assessments of injuries from different types of firearms. We compared the number of persons wounded, killed, and either wounded or killed during active shooter incidents with and without semiautomatic rifles. Methods | An active shooter incident is defined by the Federal Bureau of Investigation (FBI) as a situation in which an individual is actively engaged in killing or attempting to kill people in a confined or populated area. 3 The FBI has tracked all active shooter incidents since 2000 and has the most comprehensive data set available. 3 We retrieved active shooter incident characteristics from the publicly accessible FBI database through 2017 (accessed May 18, 2018). 3 For each incident, we extracted shooter age, name, year, location (city and state), number of people wounded, killed, and wounded or killed, place of shooting (commerce, education, government, open space, residences, health care, and house of worship), and type of firearms present (rifle, shotgun, handgun). The FBI reports do not distinguish whether a rifle was semiautomatic; therefore, for each incident in which the FBI reported that a rifle was present, a media content analysis was performed to identify semiautomatic rifle presence. An a priori search hierarchy was established in which the primary data sources were court and police documents or statements (44.9%; 35 of 78), and secondary data sources were news articles. At least 3 news articles from different media outlets were required to triangulate data. No discrepancies among sources were found. All incidents with the presence of a semiautomatic rifle were classified as semiautomatic rifle incidents regardless of other firearm presence. The Las Vegas, Nevada, shooting, which represented a statistical outlier, and the San Bernardino, California, shooting, which had more than 1 shooter present, were excluded. Negative binomial regression was used to estimate the association between presence of a semiautomatic rifle and the total numbers nonfatally wounded, killed, and either wounded or killed, and the percentage of persons who died if wounded at the incident, controlling for the place and year of shooting and the presence of other firearms. Significance was set at P < .05 (2-sided). Stata version 15.1 was used for analysis. Results | Of the 248 active shooter incidents, 76 involved a rifle, and we identified the type in all instances. A semiautomatic rifle

Assessing the potential to reduce deaths and injuries from mass shootings through restrictions on assault weapons and other high‐capacity semiautomatic firearms

“…Although offenders blocked from access to AWs and LCMs can commit crimes with other guns and smaller magazines, the logic underlying AW–LCM laws is that forcing this substitution should limit the number of shots fired in gun attacks, thus, reducing the number of people shot per attack and/or the number sustaining multiple wounds. This idea is supported by a small number of studies suggesting that attacks with semiautomatic firearms—including AWs and other guns equipped with LCMs—tend to result in more shots fired, more persons wounded, and more wounds inflicted per victim than do attacks with other firearms (Jager et al., ; Koper, ; McGonigal et al., ; Reedy & Koper, ; Richmond, Branas, Cheney, & Schwab, ; Roth & Koper, ). With respect to mass shootings in particular, AW and LCM use could conceivably affect both the prevalence and the severity of mass shootings by increasing the likelihood that shooting incidents produce enough victims to qualify as a mass shooting (Jager et al., ) and increasing the number of fatalities and injuries per mass shooting.…”

“…One step in this direction has been taken by Jager et al. (), who studied weapon types used and victim differentials in active shooter incidents documented by the FBI from 2000 to 2017. The FBI defines these incidents as cases in which an individual is killing or attempting to kill people in a confined or populated area, irrespective of the number of persons killed or wounded (see https://www.fbi.gov/about/partnerships/office-of-partner-engagement/active-shooter-resources).…”

“…Adjusting via regression modeling for the use of multiple firearms (which arguably reflects on the shooter's intentionality) and the location and year of the shooting, Jager et al. () found that incidents involving semiautomatic rifles (which accounted for 25% of the cases and serve as a rough approximation of the use of AW‐type and other LCM rifles) resulted in 97% more fatalities and 81% more wounded victims . On average, semiautomatic rifle cases involved 4.3 fatalities and 5.5 persons wounded in contrast to 2.5 fatalities and 3.0 persons wounded in other cases.…”

“…These attacks were perpetrated by offenders with a clear intent to shoot a large number of people, and they may provide the best estimates of LCM impacts under such conditions. Nonetheless, estimated LCM impacts on attack outcomes might possibly be larger or smaller if based on more comprehensive samples that included attempted, actual, and near mass shootings (e.g., Jager et al., ). The potential of LCM restrictions to reduce mass shootings might also be underestimated here if the availability of high‐capacity semiautomatics increases the likelihood that some people will attempt mass shootings.…”

Why have public mass shootings become more deadly?

“…Strong empirical evidence shows that weapon choice affects lethality. Multiple data sources indicate that active and public mass shootings committed with semiautomatics rifles and assault weapons result in more victims killed, on average, than attacks with less powerful weapons (de Jager et al., ; Follman, Aronsen, & Pan, ; Klarevas, ). Similarly, previous research findings have revealed that active and public mass shootings committed by perpetrators with multiple firearms also result in more victims killed, on average, compared with attacks with a single firearm (Klarevas, ; Lankford, , ).…”