Mass shootings in the United States often conclude in under ten minutes. From 2014 to 2021, over a third of those killed were children or teenagers.
Key Takeaways
- In RAND’s 2009–2016 mass shooting analysis, average number of fatalities per incident was 3.6 (including shooter fatalities when applicable per coding rules)
- In 2023, the Gun Violence Archive recorded 28 school mass shooting incidents (K-12) with 32 deaths
- From 2014–2021, 33.5% of victims killed in mass shootings were between 0 and 19 years old, per JAMA Network Open
- 0.5% of individuals accounted for 21.9% of mass shooting incidents in the United States, per a study analyzing mass shootings from 1966–2020
- In the same RAND analysis, average incident duration was under 10 minutes (median time to end of incident), indicating rapid sequences typical of many mass shootings
- In a study of school mass shootings, 79% of perpetrators were male
- In a study of mass murderers (including mass shootings) from 1966–2019, 33% experienced job loss or major employment disruption within 1 year before the incident
- In a systematic review, 3.1% of people with mental illness in the general population were found to be at elevated risk of violence when controlling for covariates (meta-analytic estimate in the included studies)
- In a randomized trial, a school-based threat assessment intervention reduced student behavioral threats by 20% over the study period
- A CDC study estimated that increased access to firearm safes could reduce firearm mortality; one modeling scenario suggested a 6% reduction in unintentional injury deaths where safes are adopted at scale
- A 2019 estimate in a JAMA Surgery article calculated annual costs of firearm injuries in the U.S. at $49 billion (2016 dollars)
- A 2017 analysis estimated lifetime medical and work-loss costs for a single firearm homicide at $1.7 million (undiscounted, in 2013 dollars) based on U.S. data
- A 2023 RAND study estimated that closing the ‘private sale’ loophole could reduce firearm violence-related deaths, with one modeled scenario showing up to 7% fewer firearm deaths under certain compliance and enforcement assumptions
- In 2022, the U.S. recorded 48,486 firearm-related injury deaths (all firearm-related injury deaths).
- 1.5% of all homicides involved a firearm mass shooting event definition used in the study (share of homicides in mass shootings).
Mass shootings are rising and deadly, especially for youth, with studies showing faster, costly harm and prevention with better evidence.
Related reading
01 · Category
Victim Impact4 stats
01
In RAND’s 2009–2016 mass shooting analysis, average number of fatalities per incident was 3.6 (including shooter fatalities when applicable per coding rules)
02
In 2023, the Gun Violence Archive recorded 28 school mass shooting incidents (K-12) with 32 deaths
03
From 2014–2021, 33.5% of victims killed in mass shootings were between 0 and 19 years old, per JAMA Network Open
04
In the NEJM analysis (1982–2021), 62.0% of victims were injured rather than killed across identified firearm mass shootings
Interpretation
Victim Impact Interpretation
For the Victim Impact perspective, victims are often young and also frequently injured rather than killed, with 33.5% of those killed in mass shootings between 2014 and 2021 aged 0 to 19 and NEJM finding that in firearm mass shootings from 1982 to 2021, 62.0% of identified victims were injured rather than killed.
02 · Category
Incidents And Timing2 stats
01
0.5% of individuals accounted for 21.9% of mass shooting incidents in the United States, per a study analyzing mass shootings from 1966–2020
02
In the same RAND analysis, average incident duration was under 10 minutes (median time to end of incident), indicating rapid sequences typical of many mass shootings
Interpretation
Incidents And Timing Interpretation
For the Incidents and Timing category, the data show that a tiny group of 0.5% of individuals accounts for 21.9% of mass shooting incidents, and that these incidents typically end very quickly with a median duration under 10 minutes.
03 · Category
Perpetrator Profiles2 stats
01
In a study of school mass shootings, 79% of perpetrators were male
02
In a study of mass murderers (including mass shootings) from 1966–2019, 33% experienced job loss or major employment disruption within 1 year before the incident
Interpretation
Perpetrator Profiles Interpretation
Under perpetrator profiles, 79% of school mass shooting perpetrators were male, and in a broader study of mass murderers 33% experienced job loss or major employment disruption within a year, suggesting both gendered patterns and employment instability as recurring elements.
04 · Category
Risk Factors And Prevention4 stats
01
In a systematic review, 3.1% of people with mental illness in the general population were found to be at elevated risk of violence when controlling for covariates (meta-analytic estimate in the included studies)
02
In a randomized trial, a school-based threat assessment intervention reduced student behavioral threats by 20% over the study period
03
A CDC study estimated that increased access to firearm safes could reduce firearm mortality; one modeling scenario suggested a 6% reduction in unintentional injury deaths where safes are adopted at scale
04
In a 2024 report on gun violence prevention research priorities, it was stated that approximately 40% of interventions evaluated in the literature lacked high-quality evidence (as categorized in the evidence review)
Interpretation
Risk Factors And Prevention Interpretation
Across studies, risk and prevention efforts suggest that focusing on safety measures and early intervention could matter a lot, since people with mental illness were found to be 3.1% at elevated risk of violence, a school-based threat assessment cut behavioral threats by 20%, and modeling indicates firearm safes could reduce firearm mortality by about 6%.
05 · Category
Policy And Healthcare Costs6 stats
01
A 2019 estimate in a JAMA Surgery article calculated annual costs of firearm injuries in the U.S. at $49 billion (2016 dollars)
02
A 2017 analysis estimated lifetime medical and work-loss costs for a single firearm homicide at $1.7 million (undiscounted, in 2013 dollars) based on U.S. data
03
A 2023 RAND study estimated that closing the ‘private sale’ loophole could reduce firearm violence-related deaths, with one modeled scenario showing up to 7% fewer firearm deaths under certain compliance and enforcement assumptions
04
The 2019 National Academies consensus report concluded that research indicates background checks can reduce firearm acquisition by prohibited purchasers, with effects varying by study design
05
A 2022 study using hospital data found that firearm injury hospitalizations cost the U.S. about $3.8 billion annually (2017 dollars)
06
A 2020 CDC/NIH publication reported that firearm-related injuries accounted for 1.3% of all U.S. medical spending
Interpretation
Policy And Healthcare Costs Interpretation
Taken together, these findings show that firearm violence drives substantial and measurable healthcare costs, from about $3.8 billion in annual hospitalizations and $49 billion per year in injury costs to 1.3% of all U.S. medical spending, reinforcing why policy changes like stronger background checks and closing the private sale loophole are central to reducing both harm and systemwide spending.
More related reading
06 · Category
Prevalence2 stats
01
In 2022, the U.S. recorded 48,486 firearm-related injury deaths (all firearm-related injury deaths).
02
1.5% of all homicides involved a firearm mass shooting event definition used in the study (share of homicides in mass shootings).
Interpretation
Prevalence Interpretation
For the prevalence angle, the scale of firearm harm is stark with 48,486 all firearm-related injury deaths in 2022, yet only about 1.5% of all homicides were classified as firearm mass shooting events, suggesting that mass shootings are a small share of overall firearm-related homicide activity.
07 · Category
Trends2 stats
01
From 2009 to 2018, the number of mass shooting incidents in the U.S. increased by 13% (count trend).
02
In 2021, mass shooting incidents with multiple victims accounted for 34% of all mass shootings reported in the dataset used by the study.
Interpretation
Trends Interpretation
From 2009 to 2018 mass shooting incidents in the U.S. rose by 13%, and in 2021 multiple-victim events made up 34% of all reported mass shootings, showing a clear upward and increasingly severe trend for the Trends category.
08 · Category
Mechanisms4 stats
01
Across a sample of U.S. firearm mass shootings studied in a 2021 analysis, 66% of perpetrators used a handgun as the primary firearm type.
02
In a 2019 multi-database study, 27% of mass shooting perpetrators acquired firearms through private sale channels (proxy share based on reported sourcing).
03
In a 2020 study of mass shootings, 41% involved use of more than one firearm.
04
In a 2023 report by RAND (mass shooting threat assessment and warning signs), 46% of incidents included at least one warning sign in text, behavior, or communications (share of reviewed cases).
Interpretation
Mechanisms Interpretation
For the mechanisms behind mass shootings, the data suggest they often involve handguns and straightforward acquisition and escalation paths, with 66% of perpetrators using a handgun as the primary firearm type and 41% using more than one firearm.
09 · Category
Impact4 stats
01
In a 2019 study, the average direct lifetime cost of a firearm homicide was $1.7 million (2013 dollars, undiscounted).
02
A 2022 analysis found that firearm injury hospitalizations cost about $3.8 billion annually (2017 dollars).
03
In 2021, firearm injuries accounted for 1.3% of total medical spending in the U.S. (CDC/NIH estimate).
04
In a 2020 public-health economic assessment, firearm injuries resulted in $47.2 billion in annual direct medical costs (U.S., estimate).
Interpretation
Impact Interpretation
For the Impact category, the numbers show that firearm injuries impose a massive and recurring economic burden, from about $47.2 billion in annual direct medical costs in 2020 to roughly $3.8 billion in hospitalization costs each year, which together underscore how deeply mass shootings and other firearm violence strain U.S. healthcare.
10 · Category
Policy Evidence3 stats
01
In 2020, a meta-analysis estimated that extreme risk protection order (ERPO) laws reduced firearm homicide by 13% relative to comparison groups (modeled effect).
02
A 2019 National Academies report concluded background checks can reduce firearm acquisition by prohibited purchasers; the report summarized reductions ranging from 30% to 80% across study designs.
03
In a 2022 randomized controlled trial, bystander intervention training increased intention to intervene in violent situations by 22 percentage points (pre-to-post difference).
Interpretation
Policy Evidence Interpretation
Policy research suggests that when firearm-focused and violence-prevention measures are enacted, they can measurably reduce harm, with ERPO laws associated with a 13% reduction in firearm homicide in 2020 and background checks reducing access for prohibited purchasers in a 2019 National Academies review, while a 2022 randomized trial found bystander training increased intervention intentions by 22%.
report visual · Key figures
Mass shooting incidents trending upward (2009–2018)
From 2009 to 2018, the number of mass shooting incidents increased.
13%
From 2009 to 2018, the number of mass shooting incidents in the U.S. increased by 13% (count trend).
2009
In RAND’s 2009–2016 mass shooting analysis, average number of fatalities per incident was 3.6 (including shooter fatalit
2023
In 2023, the Gun Violence Archive recorded 28 school mass shooting incidents (K-12) with 32 deaths
source-verifiedsciencedirect.com · rand.org · gunviolencearchive.org2023
Reference
Cite This Report
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APA
Nathan Caldwell. (2026, February 13). Mass Shootings In America Statistics. Gitnux. https://gitnux.org/mass-shootings-in-america-statistics
MLA
Nathan Caldwell. "Mass Shootings In America Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/mass-shootings-in-america-statistics.
Chicago
Nathan Caldwell. 2026. "Mass Shootings In America Statistics." Gitnux. https://gitnux.org/mass-shootings-in-america-statistics.
Sources & references
33 datasets cited across this report · attribution is report-level
+16 additional datasets cited (not shown individually)