When an active shooter attack unfolds in real time, one question dominates public debate: who is best positioned to stop it? The default assumption in American public life is clear; trained, uniformed police officers. They carry badges, body armor, radios, and some with years of tactical training. Civilian intervention, by contrast, is often portrayed as reckless at best and dangerous at worst.
But a new 2025 study by economists John R. Lott and Carlisle E. Moody challenges that assumption with provocative findings. Their paper, Do Armed Civilians Stop Active Shooters More Effectively Than Uniformed Police?, is the first systematic attempt to directly compare outcomes when attacks are stopped by concealed-carry permit holders versus when they are stopped by police.
The results complicate long-standing narratives about public safety, defensive gun use, and lawful civilian carry; and they raise uncomfortable questions for policymakers on all sides of the gun debate.
Here’s what the study found, how it works, and why it matters.
What the Study Examined
The researchers analyzed publicly documented active shooter events, defined narrowly as incidents where individuals attempt to kill people in public spaces. Importantly, they excluded:
- Robberies
- Gang-related shootings
- Private domestic violence
This definition mirrors the FBI’s approach and is designed to focus on attacks meant to cause mass public harm at locations such as; schools, churches, concerts, shopping centers, and workplaces.
Using FBI data and detailed media documentation, the authors identified cases where:
- A uniformed police officer stopped the shooter, or
- A civilian with a concealed-handgun permit intervened
They then compared outcomes across several concrete measures:
- Number of people killed
- Number wounded
- Total casualties
- Frequency of the attack being stopped
- Risk of injury or death to the person who intervened
Crucially, the paper confronts a major data problem head-on: it’s not always clear when armed civilians were present but chose not to act, or when a civilian helped but was misclassified. The authors emphasize that this uncertainty likely understates civilian effectiveness rather than inflates it, because unobserved non-interventions dilute the apparent impact of those who did act.
The Core Findings
Across virtually every outcome the researchers tracked, armed civilians performed at least as well as, often better than, responding police in stopping active shooting attacks.
1. Fewer Victims When Civilians Intervened
On average, attacks stopped by permit-holding civilians resulted in:
- Fewer people killed
- Fewer people wounded
- Fewer total casualties
This pattern suggests that speed matters more than firepower or formal status. Civilian defenders are often already on the scene, allowing them to engage the attacker before victim counts escalate.
2. Civilians Stopped Attacks More Frequently Than Police
When comparing only cases where intervention actually occurred:
- Civilians successfully stopped attacks at a higher rate than police officers did.
This is not necessarily a statement about superior training. Rather, it reflects response timing. Civilians who act are present at the moment violence begins in an active shooting. Police, even in the best circumstances, face minutes of delay; victims/bystanders call 911, call assessment, dispatch, travel time, threat assessment, and coordinated response.
In mass casualty events, those minutes are often the difference between two victims and twenty.
3. Lower Risk to Armed Civilians Than to Police
Perhaps most counterintuitive of all:
- Permit-holding civilians had lower injury and death rates than police officers who intervened.
This finding directly contradicts the popular fear that civilians who draw a firearm in a mass shooting automatically place themselves in greater danger.
The authors offer a nuanced explanation:
- Police officers who confront shooters during the active attack face the highest risk.
- Officers who arrive later, after the attacker has fled, barricaded, or paused, face significantly lower danger.
Civilians who intervene tend to do so immediately or not at all, often during a short, decisive encounter. Police, by contrast, are more frequently pulled into longer tactical engagements where the threat is already entrenched.
4. Constitutional Carry May Further Reduce Casualties
The study also presents tentative evidence that constitutional carry laws, which allow lawful carry without a permit, are associated with:
- Lower deaths and injuries in active shooter incidents
The authors caution that this result is less settled than the main findings. Still, they suggest that broader lawful carry may increase the probability that a capable defender happens to be present when an attack begins.
Even modest changes in that probability can have outsized effects in rare but catastrophic events.
Why This Challenges Conventional Wisdom
For decades, much of the public safety discourse has rested on a few core assumptions:
- Police are always the most effective responders to lethal threats
- Civilians are likely to panic, miss, or worsen chaos
- Armed civilians increase confusion for responding officers
- More guns necessarily mean more danger during emergency situations
This study does not deny that those risks exist. But it does show that in actual documented active shooter events, armed civilians often:
- Act faster
- Stop attacks sooner
- Reduce total victim counts more effectively
- Face no greater personal risk than police
This reframes the debate in a critical way. The question is not whether police are trained professionals, they are. The question is whether being present at the first moments of violence matters more than being in uniform.
The data suggests that, in many cases, it does.
Speed Is The Key
The longer an active shooter is free to impose their will, the higher the body count. Rapid confrontation shortens the timeline of violence, disrupts decision-making, and limits movement. Historical analysis consistently shows that immediate engagement reduces casualties and prevents attackers from reaching additional victims or consolidating control.
An armed citizen with a concealed carry permit; who is likely an intended victim and motivated by self-preservation; can represent an effective immediate response. Even the act of defending oneself and others nearby can create a ripple effect. When confronted by armed resistance, whether from law enforcement or an armed citizen, the dynamics change. Once fear of injury or death enters the attacker’s mind, they often shift from a predator to a prey mindset. No longer free to act with impunity and now focused on survival, they may surrender or be killed in the process. If an armed citizen with a concealed carry permit can make contact with the active shooter within seconds rather minutes, lives are saved.
What This Means for Gun Policy Debates
The paper’s implications land uncomfortably across the political spectrum.
For gun control advocates:
- It challenges the assumption that civilian firearms never play a positive role in public safety.
- It complicates arguments that only police should be armed in public spaces.
For gun rights supporters:
- It strengthens claims about defensive gun use in extreme cases.
- But it does not prove that widespread gun ownership is universally beneficial.
- It also does not eliminate concerns about accidents, escalation, or misuse.
Most importantly, the study suggests that concealed-carry permitting is not merely a personal liberty issue, it may be a public safety variable in rare but catastrophic crimes.
This does not mean that every public space should resemble an armed camp. But it does mean the debate can no longer hinge on the assumption that civilians are categorically ineffective or dangerous in crisis response.
The Police Role Is Still Essential
One potential misreading of this research is that it somehow renders police irrelevant. It does not.
Police remain essential for:
- Crime prevention
- Investigation
- Arrests
- Crowd control
- Emergency response
- Long-term public safety
The study is narrowly focused on the first moments of an active shooter event, a window measured in seconds and minutes before organized response is possible.
In that window, chance presence often outweighs formal authority.
Why This Research Is So Politically Volatile
Few topics in American life are as morally charged as guns and mass shootings. Research in this area faces:
- Extreme political pressure
- Media simplification
- Instant ideological sorting
Studies that suggest any positive role for armed civilians are often dismissed as propaganda. Studies that emphasize the potential positive outcome are often accused of fear-mongering. This paper enters that minefield by attempting something rare: direct outcome comparison.
It doesn’t ask whether guns are good or bad in the abstract. It asks:
When a mass shooting is already happening, who actually stops it more effectively?
That is an uncomfortable but necessary question.
The Bottom Line
The 2025 Lott–Moody study provides some of the strongest empirical evidence to date that civilians with concealed-handgun permits often stop active shooter attacks more effectively than uniformed police, and with lower personal risk to themselves.
That finding directly challenges:
- Common media narratives
- Conventional public safety assumptions
- Simplistic policy slogans on both sides
At the same time, the study’s scope is narrow, the data imperfect, and the broader consequences of increased civilian gun carrying remain unresolved.
The takeaway is not that “guns solve everything” or that “police are ineffective.” The takeaway is far more nuanced, and far more difficult:
In the first chaotic moments of a mass shooting, being on scene may matter more than being in uniform.
That reality should force a more honest, evidence-driven discussion about how society thinks about prevention, response, and the complex role of armed civilians in public life.
