Paper: Do armed civilians stop active shooters more effectively than uniformed police?

Since 2000, the FBI has tracked active shooting cases, an event where an individual actively attempts to kill people in a public place, excluding shootings tied to robberies or gang violence.

An “active shooting” could be as simple as a single shot fired at a lone human target, even if the shooter misses, to a mass shooting. Yet while this data has been collected by the FBI, there have been no studies by the FBI nor academics that systematically examine police performance in stopping these attacks. One approach is to compare police with the alternative: civilians who have permitted concealed handguns. Comparisons can be made in the rate that they stop attacks, whether they increase or decrease the number of casualties, whether they accidentally shoot bystanders, and whether the individuals attempting to stop the attack were wounded or killed by the criminal.

A literature has emerged on mass public shootings where four or more people have been murdered in a public place. These studies have concentrated only on the issues of the rate of attacks in places that allow people to carry permitted concealed handguns or other gun control laws. There have been no studies on the much broader set of active shooting cases and none that focus on the effectiveness of police in stopping attacks.

Civilians will inevitably make mistakes and won’t stop every active shooter situation, and most don’t receive the same level of training as police. So it’s reasonable to expect that, on average, police might perform better in confronting active shooters. Indeed, it is possible that permit holders could make active shooting attacks worse by getting in the way. But the right comparison isn’t against perfection.

Uniform disadvantage, non-uniform advantage

Police officers often face tactical disadvantages because their uniforms make them easy targets. Attackers who see a uniformed officer can wait for the officer to leave, move on to another target, or strike first knowing the officer is armed. The concern over these tactical disadvantages is the reason that air marshals on airplanes do not wear uniforms.

Ideally, we would also compare non-uniformed officers to officers, but the sample of non-uniformed officers is too small, with only a couple cases.

Civilians, by contrast, can intervene when in places they are allowed to carry concealed weapons before an attacker notices them. They also outnumber on-duty police officers by a wide margin. In 2024, 21.5 million Americans — about 8.2% of adults — held concealed handgun permits. In addition, 29 states allowed constitutional carry, which requires no permit at all.

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Surveys show that 7.2% of likely voters carry all the time, and another 8.4% carry some of the time. Compare that to the roughly 671,000 full-time sworn law enforcement officers in 2020. If only a third are on duty at any given time, that leaves about 262,522 officers to protect a population of 340 million — less than 0.1% of the population.

Even though police have more training and experience, uniformed officers face greater risks and challenges. They’re less likely to be near an attack when it occurs, and when they are, they’re more likely to be targeted and killed. This paper is the first to compare outcomes in active shooter events based on whether armed civilians or police intervened, highlighting key differences in effectiveness and risk.

FBI's data focus: cases that make national news

The FBI collects data on “active shooter” incidents — i.e., one or more individuals actively engaged in killing or attempting to kill people in a public area. The FBI excludes gang and drug-related violence, as well as other criminal acts, such as a robbery, as their goal is to focus on those cases that get national news attention where an attacker’s sole goal is to murder people in a public place, such as a mall, school, or movie theater.

Because law enforcement agencies don’t collect this data in crime reports, the FBI worked with the Advanced Law Enforcement Rapid Response Training Center at Texas State University to collect these cases from news reports. Research done at the Office of Justice Programs and Office of Legal Policy, U.S. Department of Justice, points out that while the FBI generally does a good job of identifying active shooting cases, they only include some self-defense cases and misidentify others.

First on the scene, not seen as threat

The results favor intervention by armed citizens. Unlike uniformed police officers, armed citizens are already on the scene and don’t stand out as obvious threats to a shooter. In contrast, police face significant disadvantages. They rarely happen to be present when an attack begins, and if a potential attacker sees an officer nearby, he’s likely to either wait for the officer to leave the area or move on to a new target. Shooters who decide not to alter their plans will likely choose to attack the visible uniformed officers first. While taking on an officer may not be easy, it becomes the first objective when the shooter sees that the officer is armed and in uniform.

Our findings show that armed citizens are significantly more effective than uniformed police at stopping potential mass shootings. This result isn’t a criticism of law enforcement; it simply reflects the tactical realities they face. Their uniforms make them visible targets, and longer response times give attackers more opportunity to cause harm.

Results favor armed citizens

These results also suggest a broader conclusion: Having armed citizens dispersed throughout public spaces improves public safety. Conversely, gun-free zones are likely to be counterproductive, a view supported by other research showing that the overwhelming majority of mass public shootings occur in such zones. Armed citizens are not trained like police officers as to the correct response to an active shooter event. Consequently, they could in theory make the situation worse by inserting themselves into the event. Our analysis soundly rejects that idea. In fact, we find the opposite to be true: Armed citizens do not interfere with police, and in active shooter situations, they reduce deaths and injuries significantly more effectively than the police.

Read the full report at crimeresearch.org/2025/04/new-research-do-armed-civilians-stop-active-shooters-more-effectively-than-uniformed-police.

Republished with permission from Crime Prevention Research Center. Sign up for CPRC's newsletters at crimepreventionresearchcenter.nationbuilder.com.