THIS DATASET WAS LAST UPDATED AT 2:11 AM EASTERN ON JULY 15

OVERVIEW

2019 had the most mass killings since at least the 1970s, according to the Associated Press/USA TODAY/Northeastern University Mass Killings Database.

In all, there were 45 mass killings, defined as when four or more people are killed excluding the perpetrator. Of those, 33 were mass shootings . This summer was especially violent, with three high-profile public mass shootings occurring in the span of just four weeks, leaving 38 killed and 66 injured.

A total of 229 people died in mass killings in 2019.

The AP's analysis found that more than 50% of the incidents were family annihilations, which is similar to prior years. Although they are far less common, the 9 public mass shootings during the year were the most deadly type of mass murder, resulting in 73 people's deaths, not including the assailants.

One-third of the offenders died at the scene of the killing or soon after, half from suicides.

About this Dataset

The Associated Press/USA TODAY/Northeastern University Mass Killings database tracks all U.S. homicides since 2006 involving four or more people killed (not including the offender) over a short period of time (24 hours) regardless of weapon, location, victim-offender relationship or motive. The database includes information on these and other characteristics concerning the incidents, offenders, and victims.

The AP/USA TODAY/Northeastern database represents the most complete tracking of mass murders by the above definition currently available. Other efforts, such as the Gun Violence Archive or Everytown for Gun Safety may include events that do not meet our criteria, but a review of these sites and others indicates that this database contains every event that matches the definition, including some not tracked by other organizations.

This data will be updated periodically and can be used as an ongoing resource to help cover these events.

Using this Dataset

To get basic counts of incidents of mass killings and mass shootings by year nationwide, use these queries:

Mass killings by year

Mass shootings by year

To get these counts just for your state:

Filter killings by state

Definition of "mass murder"

Mass murder is defined as the intentional killing of four or more victims by any means within a 24-hour period, excluding the deaths of unborn children and the offender(s). The standard of four or more dead was initially set by the FBI.

This definition does not exclude cases based on method (e.g., shootings only), type or motivation (e.g., public only), victim-offender relationship (e.g., strangers only), or number of locations (e.g., one). The time frame of 24 hours was chosen to eliminate conflation with spree killers, who kill multiple victims in quick succession in different locations or incidents, and to satisfy the traditional requirement of occurring in a “single incident.”

Offenders who commit mass murder during a spree (before or after committing additional homicides) are included in the database, and all victims within seven days of the mass murder are included in the victim count. Negligent homicides related to driving under the influence or accidental fires are excluded due to the lack of offender intent. Only incidents occurring within the 50 states and Washington D.C. are considered.

Methodology

Project researchers first identified potential incidents using the Federal Bureau of Investigation’s Supplementary Homicide Reports (SHR). Homicide incidents in the SHR were flagged as potential mass murder cases if four or more victims were reported on the same record, and the type of death was murder or non-negligent manslaughter.

Cases were subsequently verified utilizing media accounts, court documents, academic journal articles, books, and local law enforcement records obtained through Freedom of Information Act (FOIA) requests. Each data point was corroborated by multiple sources, which were compiled into a single document to assess the quality of information.

In case(s) of contradiction among sources, official law enforcement or court records were used, when available, followed by the most recent media or academic source.

Case information was subsequently compared with every other known mass murder database to ensure reliability and validity. Incidents listed in the SHR that could not be independently verified were excluded from the database.

Project researchers also conducted extensive searches for incidents not reported in the SHR during the time period, utilizing internet search engines, Lexis-Nexis, and Newspapers.com. Search terms include: [number] dead, [number] killed, [number] slain, [number] murdered, [number] homicide, mass murder, mass shooting, massacre, rampage, family killing, familicide, and arson murder. Offender, victim, and location names were also directly searched when available.

This project started at USA TODAY in 2012.

Contacts

Contact AP Data Editor Justin Myers with questions, suggestions or comments about this dataset at jmyers@ap.org. The Northeastern University researcher working with AP and USA TODAY is Professor James Alan Fox, who can be reached at j.fox@northeastern.edu or 617-416-4400.

As of September 2024, California had the most mass shootings in the United States, with 26 total shootings since 1982. The source defines a mass shooting as a shooting where three or more people were killed. Recently, a mass shooting occurred in the state of Maine on October 26, 2023, during which one of the highest number of fatalities from a mass shooting was recorded after Robert Card opened fire in a bowling alley and a bar, killing 18 and injuring 13 others. Firearms in the U.S. Mass shootings in the United States are disturbingly common. In comparison with other Western countries, there are significantly more shootings in the U.S., which some theorize is due to the relatively lax gun control laws. Gun control laws in the U.S. are dependent on the state, and the right to own a firearm is enshrined in the United States Constitution. Mass shootings The worst mass shooting in the U.S. was the Las Vegas Strip massacre in 2017, which resulted in 58 deaths and 546 injuries. 13 of the worst mass shootings in the United States have occurred since 2015 and the vast majority of these incidents in the U.S. have been carried out by shooters who are White and male.

As of September 4, there were two mass shootings in the United States in 2024. This is compared to one mass shooting in 1982, one in 2000, and 12 mass shootings in 2022 and 2023. School shootings The United States sees the most school shootings in the world. Some motivations for school shootings included depression, seeking revenge, and bullying. As a result of the large amount of school shootings, gun control has become a central topic in U.S. politics. This widespread problem happens across the United States; however California saw the highest number of K-12 school shootings in the United States since 1970. However, the deadliest school shooting (as of October 2023) was the Virginia Tech massacre in 2007. This tragedy left 33 dead and 23 injured. Mass shooting issues Mass shootings happen when there are several injuries or deaths from a firearm-related violence. Throughout the last century, mass shootings have become an epidemic in the United States. However, despite the increase in mass shootings and number of casualties, the U.S. government has done little to prevent future shootings from happening. As a result of the lack of cooperation in politics, mass shootings have become an important issue for Generation Z living in the United States. Furthermore, having the right to bear arms is a popular belief in the U.S. and the percentage of households in the United States owning at least one firearm has remained somewhat steady since 1972.

On October 1, 2017, the highest number of fatalities from a mass shooting in the United States was recorded when Stephen Paddock attacked a crowd of concert-goers on the Las Vegas strip, killing 58 and injuring 546 others, then taking his own life before authorities could apprehend him. Most recently, one of the worst mass shootings in the U.S. occurred in Maine on October 26, 2023, when Robert Card, an Army reservist and firearms instructor, opened fire in a bowling alley and a bar, killing 18 and injuring 13 others. Card then became the focus of a two-day-long manhunt, until he was found dead from a self-inflicted gunshot.

Between 1982 and September 2024, 82 out of the 151 mass shootings in the United States were carried out by White shooters. By comparison, the perpetrator was African American in 26 mass shootings, and Latino in 12. When calculated as percentages, this amounts to 54 percent, 17 percent, and eight percent respectively. Race of mass shooters reflects the U.S. population Broadly speaking, the racial distribution of mass shootings mirrors the racial distribution of the U.S. population as a whole. While a superficial comparison of the statistics seems to suggest African American shooters are over-represented and Latino shooters underrepresented, the fact that the shooter’s race is unclear in around nine percent of cases, along with the different time frames over which these statistics are calculated, means no such conclusions should be drawn. Conversely, looking at the mass shootings in the United States by gender clearly demonstrates that the majority of mass shootings are carried out by men. Mass shootings and mental health With no clear patterns between the socio-economic or cultural background of mass shooters, increasing attention has been placed on mental health. Analysis of the factors Americans considered to be to blame for mass shootings showed 80 percent of people felt the inability of the mental health system to recognize those who pose a danger to others was a significant factor. This concern is not without merit – in over half of the mass shootings since 1982, the shooter showed prior signs of mental health issues, suggesting improved mental health services may help deal with this horrific problem. Mass shootings and guns In the wake of multiple mass shootings, critics have sought to look beyond the issues of shooter identification and their influences by focusing on their access to guns. The majority of mass shootings in the U.S. involve firearms which were obtained legally, reflecting the easy ability of Americans to purchase and carry deadly weapons in public. Gun control takes on a particular significance when the uniquely American phenomenon of school shootings is considered. The annual number of incidents involving firearms at K-12 schools in the U.S. was over 100 in each year since 2018. Conversely, similar incidents in other developed countries exceptionally rare, with only five school shootings in G7 countries other than the U.S. between 2009 and 2018.

The dataset contains detailed information on mass shooting attacks that took place in the United States of America in 1966 - 2017.

Source: https://www.kaggle.com/zusmani/us-mass-shootings-last-50-years/version/4#Mass%20Shootings%20Dataset%20Ver%205.csv

As of September 4, eight people were killed in mass shootings in the United States in 2024. A total 1,159 victims were fatally injured during mass shootings in the United States between 1982 and September 4, 2024.

The graph displays the number of mass shootings in the U.S. by year from 1982 to 2024, with the x-axis representing the years and the y-axis showing the number of incidents per year. The data reveals a significant increase in mass shootings over time, with the highest numbers recorded in 2018, 2022, and 2023, each with 12 incidents. In the early years (1982-2000), mass shootings were relatively low, typically one to three incidents per year. However, after 2012 (7 incidents), the numbers began rising sharply, with 2017 recording 11 incidents and 2019 reaching 10. The data highlights a concerning upward trend in mass shootings over the past two decades.

BackgroundGun violence has shortened the average life expectancy of Americans, and better knowledge about the root causes of gun violence is crucial to its prevention. While some empirical evidence exists regarding the impacts of social and economic factors on violence and firearm homicide rates, to the author’s knowledge, there has yet to be a comprehensive and comparative lagged, multilevel investigation of major social determinants of health in relation to firearm homicides and mass shootings.Methods and findingsThis study used negative binomial regression models and geolocated gun homicide incident data from January 1, 2015, to December 31, 2015, to explore and compare the independent associations of key state-, county-, and neighborhood-level social determinants of health—social mobility, social capital, income inequality, racial and economic segregation, and social spending—with neighborhood firearm-related homicides and mass shootings in the United States, accounting for relevant state firearm laws and a variety of state, county, and neighborhood (census tract [CT]) characteristics. Latitude and longitude coordinates on firearm-related deaths were previously collected by the Gun Violence Archive, and then linked by the British newspaper The Guardian to CTs according to 2010 Census geographies. The study population consisted of all 74,134 CTs as defined for the 2010 Census in the 48 states of the contiguous US. The final sample spanned 70,579 CTs, containing an estimated 314,247,908 individuals, or 98% of the total US population in 2015. The analyses were based on 13,060 firearm-related deaths in 2015, with 11,244 non-mass shootings taking place in 8,673 CTs and 141 mass shootings occurring in 138 CTs. For area-level social determinants, lag periods of 3 to 17 years were examined based on existing theory, empirical evidence, and data availability. County-level institutional social capital (levels of trust in institutions), social mobility, income inequality, and public welfare spending exhibited robust relationships with CT-level gun homicide rates and the total numbers of combined non-mass and mass shooting homicide incidents and non-mass shooting homicide incidents alone. A 1–standard deviation (SD) increase in institutional social capital was linked to a 19% reduction in the homicide rate (incidence rate ratio [IRR] = 0.81, 95% CI 0.73–0.91, p

The data on mass shootings is from https://www.gunviolencearchive.org/ . This dataset on mass shootings for the period 2014-2023 was provided on Feb 19, 2024 by the Data Manager (Ms. Sharon Williams) at the Gun Violence Archive (https://www.gunviolencearchive.org/) on a data request. Minimal curation was done on this data – the date variable was split into year, month and day. See the codebook for full details.A mass shooting is defined as four or more people injured or killed, because of firearms, excluding the shooter.The curated datasets are included here along with a research question and guiding questions.For information of how this data is collected, go to: https://www.gunviolencearchive.org/explainerDefinition for mass shooting and mass murder from the above website is given verbatim below:Mass Shooting Methodology and Reasoning: Mass Shootings are, for the most part an American phenomenon. While they are generally grouped together as one type of incident they are several different types including public shootings, bar/club incidents, family annihilations, drive-by, workplace and those which defy description but with the established foundation definition being that they have a minimum of four victims shot, either injured or killed, not including any shooter who may also have been killed or injured in the incident. GVA also presents the count of Mass Murder which, like the FBI's definition is four or more victims, killed, not including the shooter. Mass Murder by gun is a subset of the Mass Shooting count.

Since 1982, an astonishing 145 mass shootings have been carried out in the United States by male shooters. In contrast, only four mass shootings (defined by the source as a single attack in a public place in which four or more victims were killed) have been carried out by women. Gun ownership in the U.S. Possession of firearms in the United States is protected by the 2nd Amendment of the Constitution and has been a defining aspect of American civil liberties since the writing of the Bill of Rights. It is estimated that the United States has the highest rate of civilian-owned firearms in the world, and Americans continually poll against handgun restrictions. Mass shootings However, with high gun ownership comes high responsibility. The United States consistently faces numerous mass shootings each year, particularly in schools. The five deadliest mass shootings have all occurred since 2007, with the deadliest being the Las Vegas Strip massacre in 2017, which claimed the lives of 58 people and injured 546 more.

Gun ownership in the United States is the highest in the world, and constitutionally protected by the Second Amendment to the United States Constitution. Firearms are widely used in the United States for self-defence, hunting, and recreational uses, such as target shooting.

Source: https://www.kaggle.com/datasets/nidzsharma/us-mass-shootings-19822023

https://www.googleapis.com/download/storage/v1/b/kaggle-user-content/o/inbox%2F13190980%2F56c639fee11c268267f9cf4ece33cf6a%2Fnewplot%20(6).png?generation=1680562776580204&alt=media" alt="">

Data columns:

• 0 case
• 1 location
• 2 date
• 3 summary
• 4 fatalities
• 5 injured
• 6 total_victims
• 7 location.1
• 8 age_of_shooter
• 9 prior_signs_mental_health_issues - Cleaned
• 10 mental_health_details - Cleaned
• 11 weapons_obtained_legally
• 12 where_obtained
• 13 weapon_type
• 14 weapon_details
• 15 race - cleaned
• 16 gender - cleaned
• 17 latitude - filled from location with Google Maps API
• 18 longitude - filled from location with Google Maps API
• 19 type
• 20 year - retrieved from date column
• 21 quarter - retrieved from date column
• 22 half - retrieved from date column
• 23 month_name - retrieved from date column
• 24 day_of_week - retrieved from date column
• 25 age_group - "Teenage", "Early Adulthood", "Middle Adulthood", "Old Age"
• 26 decade - retrieved from date
• 27 name - retrieved from splitting summary
• 28 current_age - retrieved from splitting summary
• 29 description - retrieved from splitting summary

The graph displays the Top 5 states with the most mass shootings in the U.S. from 1982 to 2024, with the x-axis representing states and the y-axis showing the total number of mass shootings recorded in each state. California leads with 26 mass shootings, followed by Florida and Texas, each with 13 incidents. Other states with high numbers include Colorado (8), Washington (7). The data shows that mass shootings have occurred across a wide range of states, with some experiencing significantly more incidents than others.

Context

This is a copy of https://www.kaggle.com/zusmani/us-mass-shootings-last-50-years but with NaN coordinates (Latitude and Longitude) fixed.

Social determinants and the total number of mass shooting homicide incidents at the CT level in the contiguous US, 2015.

Mass shootings are becoming a more common occurrence in the United States. Data show that mass shootings increased steadily over the past nearly 50 years. Crucial is that the wide-ranging adverse effects of mass shootings generate negative mental health outcomes on millions of Americans, including fear, anxiety, and ailments related to such afflictions. This study extends previous research that finds a strong positive relationship between income inequality and mass shootings by examining the effect of household income as well as the interaction between inequality and income. To conduct our analyses, we compile a panel dataset with information across 3,144 counties during the years 1990 to 2015. Mass shootings was measured using a broad definition of three or more victim injuries. Income inequality was calculated using the post-tax version of the Gini coefficient. Our results suggest that while inequality and income alone are both predictors of mass shootings, their impacts on mass shootings are stronger when combined via interaction. Specifically, the results indicate areas with the highest number of mass shootings are those that combine both high levels of inequality and high levels of income. Additionally, robustness checks incorporating various measures of mass shootings and alternative regression techniques had analogous results. Our findings suggest that to address the mass shootings epidemic at its core, it is essential to understand how to stem rising income inequality and the unstable environments that we argue are created by such inequality.

How do events that highlight a policy issue impact political preferences? In this paper, I analyze the impact of mass shootings on voter behavior. I show that, conditional on population, mass shootings are largely random events. Using a difference-in-differences strategy, I find that mass shootings result in a 1.7 percentage point loss in Republican vote share in counties where they occur. Identification that relies on comparing successful and failed mass shootings yields similar results. Mass shootings lead to an increase in the salience of gun policy and increase the divide on gun policy among both voters and politicians. Democrats (Republicans) tend to demand even stricter (looser) gun control after mass shootings. These results suggest that increasing the salience of an issue may polarize the electorate.

Handguns are the most common weapon type used in mass shootings in the United States, with a total of 167 different handguns being used in 117 incidents between 1982 and September 2024. These figures are calculated from a total of 151 reported cases over this period, meaning handguns are involved in about 78 percent of mass shootings. The involvement of semi-automatic rifles in mass shootings Owing to their use in several high-profile mass shootings, there has been much public discussion over the suitability or necessity of assault weapons for the purpose of self-defense. While any definition of assault weapon is contentious, semi-automatic rifles are generally the main focus of debates around this issue. Since 1982, there has been a known total 65 mass shootings involving rifles, mostly semi-automatics. This figure is underreported, however, as it excludes the multiple semi-automatic (and fully automatic) rifles used in the 2017 Las Vegas Strip massacre – the worst mass shooting in U.S. history, killing 58 and wounding 546. In fact, semi-automatic rifles were featured in four of the five deadliest mass shootings, being used in the Orlando nightclub massacre, Sandy Hook Elementary massacre and Texas First Baptist Church massacre. Mass shootings and gun control Despite evidence of strict gun control measures reducing the frequency and severity of mass shootings in countries like Australia, citizens in the United States remain deeply divided over the issue. According to a survey about the expected impact of gun laws on the number of mass shootings, a slim majority of Americans believe that gun control measures will have little-to-no effect. Most likely, this opinion is influenced by an underlying commitment among many in the U.S. to the greater importance of protecting gun ownership rights than limiting access to firearms. This sits in sharp contrast to many other developed countries. For example, most Canadians support a ban on civilian owned firearms.

How do events that highlight a policy issue impact political preferences? In this paper, I analyze the impact of mass shootings on voter behavior. I show that, conditional on population, mass shootings are largely random events. Using a difference-in-differences strategy, I find that mass shootings result in a 1.7 percentage point loss in Republican vote share in counties where they occur. Identification that relies on comparing successful and failed mass shootings yields similar results. Mass shootings lead to an increase in the salience of gun policy and increase the divide on gun policy among both voters and politicians. Democrats (Republicans) tend to demand even stricter (looser) gun control after mass shootings. These results suggest that increasing the salience of an issue may polarize the electorate.

The study examines the behavioral underpinnings of three types of United States-based offenders: solo terrorists, lone-actor terrorists, and individuals who engage in mass casualty violence but lack an ideological motivation (aka mass murderers). In particular, the researchers compare the developmental, antecedent behavioral, and ideological factors that crystallize within the offender and are later expressed behaviorally via an attack. The data address the following research questions: What are the similarities and differences between lone actor terrorists and solo mass murderers, in terms of sociodemographic characteristics and behavioral traits prior to, during, and after their attack? Can risk factors associated with delinquency and criminal offenses also help predict low-likelihood, high impact events such as lone actor terrorist attacks and mass murders? Do these factors remain the same over time? To complete the research objectives, the researchers used an open source methodological design, relying solely on text materials available within the public domain. Data were coded and then statistically analyzed using bivariate and multivariate tests. The sample (n = 186) was limited to United States-based offenders who operated between 1990 and 2013 and were identifiable through publicly available materials.