11 datasets found
  1. d

    Mass Killings in America, 2006 - present

    • data.world
    csv, zip
    Updated Jul 17, 2025
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    The Associated Press (2025). Mass Killings in America, 2006 - present [Dataset]. https://data.world/associatedpress/mass-killings-public
    Explore at:
    zip, csvAvailable download formats
    Dataset updated
    Jul 17, 2025
    Authors
    The Associated Press
    Time period covered
    Jan 1, 2006 - Jul 4, 2025
    Area covered
    Description

    THIS DATASET WAS LAST UPDATED AT 8:11 PM EASTERN ON JULY 16

    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.

  2. Data from: National Violent Death Reporting System (NVDRS)

    • catalog.data.gov
    • healthdata.gov
    • +6more
    Updated Jul 26, 2023
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Centers for Disease Control and Prevention, Department of Health & Human Services (2023). National Violent Death Reporting System (NVDRS) [Dataset]. https://catalog.data.gov/dataset/national-violent-death-reporting-system-nvdrs
    Explore at:
    Dataset updated
    Jul 26, 2023
    Description

    The National Violent Death Reporting System (NVDRS) provides states and communities with a clearer understanding of violent deaths to guide local decisions about efforts to prevent violence and helps them track progress over time. To stop violent deaths, we must first understand all the facts. Created in 2002, the NVDRS is a surveillance system that pulls together data on violent deaths in 18 states (see map below), including information about homicides, such as homicides perpetrated by a intimate partner (e.g., boyfriend, girlfriend, wife, husband), child maltreatment (or child abuse) fatalities, suicides, deaths where individuals are killed by law enforcement in the line of duty, unintentional firearm injury deaths, and deaths of undetermined intent. These data are supported by WISQARS, an interactive query system that provides data on injury deaths, violent deaths, and nonfatal injuries.

  3. Mapping Injury, Overdose, and Violence - Census Tract

    • healthdata.gov
    • data.virginia.gov
    • +1more
    application/rdfxml +5
    Updated Jan 15, 2025
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    data.cdc.gov (2025). Mapping Injury, Overdose, and Violence - Census Tract [Dataset]. https://healthdata.gov/dataset/Mapping-Injury-Overdose-and-Violence-Census-Tract/kuv7-59zk
    Explore at:
    csv, application/rdfxml, xml, tsv, application/rssxml, jsonAvailable download formats
    Dataset updated
    Jan 15, 2025
    Dataset provided by
    data.cdc.gov
    Description

    This file contains death counts and death rates for drug overdose, suicide, homicide and firearm injuries by census tract of residence (additional datasets exist for other levels of geography). The data is grouped by 2 different time periods including yearly and trailing twelve months. Please see data dictionary for intents and mechanisms included in each measure.

    When there are 1-9 deaths in an area, CDC uses a Bayesian model to calculate rates. A Bayesian model is a type of statistical model often used in geographic analysis. This model can improve stability of the rates in lower population areas and protects privacy by taking into account information from neighboring areas.

  4. u

    Police Annual Statistical Report - Shooting Occurrences

    • data.urbandatacentre.ca
    • ckan0.cf.opendata.inter.prod-toronto.ca
    • +1more
    Updated Oct 3, 2024
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    (2024). Police Annual Statistical Report - Shooting Occurrences [Dataset]. https://data.urbandatacentre.ca/dataset/city-toronto-police-annual-statistical-report-shooting-occurrences
    Explore at:
    Dataset updated
    Oct 3, 2024
    Description

    The Toronto’s Police Service Annual Statistical Report (ASR) is a comprehensive overview of police related statistics including reported crimes, victims of crime, search of persons, firearms, traffic collisions, personnel, budget, communications, public complaints, regulated interactions and other administrative information. This dataset includes all shooting occurrences from 2014 to 2019 by occurred date aggregated by Division. This data includes all shooting-related events reported to the Toronto Police Service, including, but not limited to, those that may have been deemed unfounded after investigation. Data is accurate as of the date and time of reporting. In accordance with the Municipal Freedom of Information and Protection of Privacy Act, the Toronto Police Service has taken the necessary measures to protect the privacy of individuals involved in the reported occurrences. No personal information related to any of the parties involved in the occurrence will be released as open data. The data has been aggregated by year, category, subtype and geographic division. As there is no criminal offence code for shootings, a shooting occurrence number may also be present in other data sets including, but not limited to, assault and robbery. Note: The further breakdown of this information at the event level will be made available in the future releases of the Shootings open data. Shootings in this data set include both firearm discharges and shooting events, which are defined as follows: Shooting Event/Occurrence: Any incident in which a projectile is discharged from a firearm (as defined under the Criminal Code of Canada) and injures a person. This excludes events such as suicide and police involved firearm discharges. Firearm Discharge: Any incident where evidence exists that a projectile was discharged from a firearm (as defined under the Criminal Code of Canada) including accidental discharge (non-police), celebratory fire, drive-by etc. Persons Injured (previously classified as “victims”): A person who was struck by a bullet(s) as a result of the discharge of a firearm (as defined under the Criminal Code of Canada). This excludes events such as suicide, police-involved event or where the weapon used was not a real firearm (such as pellet gun, air pistol, “sim-munition” etc.) Injury Levels

  5. f

    Risk associated between firearm prevalence and suicide rates.

    • figshare.com
    xls
    Updated Jun 2, 2023
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Caillin Langmann (2023). Risk associated between firearm prevalence and suicide rates. [Dataset]. http://doi.org/10.1371/journal.pone.0234457.t003
    Explore at:
    xlsAvailable download formats
    Dataset updated
    Jun 2, 2023
    Dataset provided by
    PLOS ONE
    Authors
    Caillin Langmann
    License

    Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
    License information was derived automatically

    Description

    Risk associated between firearm prevalence and suicide rates.

  6. Gun Violence Archive

    • datacatalog.med.nyu.edu
    Updated May 6, 2025
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Gun Violence Archive (2025). Gun Violence Archive [Dataset]. https://datacatalog.med.nyu.edu/dataset/10740
    Explore at:
    Dataset updated
    May 6, 2025
    Dataset authored and provided by
    Gun Violence Archivehttps://www.gunviolencearchive.org/
    Time period covered
    Jan 1, 2013 - Present
    Area covered
    Arizona, Maryland, New Mexico, United States, Rhode Island, Iowa, Texas, Illinois, Connecticut, Maine
    Description

    The Gun Violence Archive (GVA) is an online archive of gun violence incidents collected from over 7,500 law enforcement, media, government and commercial sources daily in an effort to provide near-real time data about the results of gun violence. GVA was established in 2013 an independent data collection and research group to provide comprehensive data for the national conversation regarding gun violence.

    GVA catalogs both incidents of gun-related deaths and incidents where a victim was injured by shooting or by a victim who was the subject of an armed robber or home invader. Incidents of defensive gun use, homeowners who stop a home invasion, store clerks who stop a robbery, individuals who stop an assault or rape with a gun are also collected. The two exceptions to the near real-time collection are suicides by gun, which are collected quarterly and annually due to differing distribution methods by government agencies, and for armed robberies with no injuries or DGU characteristics, which are collected in aggregate with law enforcement quarterly and annual reports. GVA also records incidents of Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) and local law enforcement involvement in recovering illegal or stolen weapons; incidents where guns were reported stolen from homes, vehicles, and businesses; incidents where Airsoft or BB guns are used as weapons (but not where they are used in general vandalism or delinquency); and TSA data of guns illegally taken through airport security points. Incident data are categorized by number of deaths, number of injuries, number of children, number of teens, mass shootings, officers shot, suspect shot by officer, home invasion, defensive use, and unintentional shooting.

  7. n

    Data from: Urban scaling of firearm violence, ownership and accessibility in...

    • ultraviolet.library.nyu.edu
    bin, zip
    Updated Apr 25, 2025
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Rayan Succar; Rayan Succar; Maurizio Porfiri; Maurizio Porfiri (2025). Urban scaling of firearm violence, ownership and accessibility in the United States [Dataset]. http://doi.org/10.58153/xv1tw-98j62
    Explore at:
    bin, zipAvailable download formats
    Dataset updated
    Apr 25, 2025
    Dataset provided by
    New York University
    Authors
    Rayan Succar; Rayan Succar; Maurizio Porfiri; Maurizio Porfiri
    License

    https://www.gnu.org/licenses/gpl-3.0-standalone.htmlhttps://www.gnu.org/licenses/gpl-3.0-standalone.html

    Area covered
    United States
    Description

    The United States is ranked first in gun possession globally and is among the countries suffering the most from firearm violence. Several aspects of the US firearm ecosystem have been detailed over the years, mostly focusing on nation- or state-level phenomena. Systematic, high-resolution studies that compare US cities are largely lacking, leaving several questions open. For example, how does firearm violence vary with the population size of a US city? Are guns more prevalent and accessible in larger cities? In search of answers to these questions, we apply urban scaling theory, which has been instrumental in understanding the present and future of urbanization for the past 15 years. We collate a dataset about firearm violence, accessibility and ownership in 929 cities, ranging from 10,000 to 20,000,000 people. We discover superlinear scaling of firearm violence (measured through the incidence of firearm homicides and armed robberies) and sublinear scaling of both firearm ownership (inferred from the percentage of suicides that are committed with firearm) and firearm accessibility (measured as the prevalence of federal firearm-selling licenses). To investigate the mechanism underlying the US firearm ecosystem, we establish a novel information-theoretic methodology that infers associations from the variance of urban features about scaling laws. We unveil influence of violence and firearm accessibility on firearm ownership, which we model through a Cobb–Douglas function. Such an influence suggests that self-protection could be a critical driver of firearm ownership in US cities, whose extent is moderated by access to firearms.

  8. Mapping Injury, Overdose, and Violence - County

    • data.virginia.gov
    • healthdata.gov
    • +1more
    csv, json, rdf, xsl
    Updated Jan 13, 2025
    + more versions
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Centers for Disease Control and Prevention (2025). Mapping Injury, Overdose, and Violence - County [Dataset]. https://data.virginia.gov/dataset/mapping-injury-overdose-and-violence-county
    Explore at:
    xsl, csv, json, rdfAvailable download formats
    Dataset updated
    Jan 13, 2025
    Dataset provided by
    Centers for Disease Control and Preventionhttp://www.cdc.gov/
    Description

    This file contains death counts and death rates for drug overdose, suicide, homicide and firearm injuries by county of residence (additional datasets exist for other levels of geography). The data is grouped by 2 different time periods including yearly and trailing twelve months. Please see data dictionary for intents and mechanisms included in each measure.

    When there are 1-9 deaths in an area, CDC uses a Bayesian model to calculate rates. A Bayesian model is a type of statistical model often used in geographic analysis. This model can improve stability of the rates in lower population areas and protects privacy by taking into account information from neighboring areas.

  9. f

    Data_Sheet_1_Reducing firearm access for youth at risk for suicide in a...

    • frontiersin.figshare.com
    • figshare.com
    pdf
    Updated May 22, 2024
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Sofia Chaudhary; Kiesha Fraser Doh; Emilie Morris; Caroline Chivily; Donnetta S. Washington; Scott E. Gillepsie; Andrew Jergel; Sarah Lazarus; Angela Costa; Nathan Call; Jonathan Rupp; Harold K. Simon (2024). Data_Sheet_1_Reducing firearm access for youth at risk for suicide in a pediatric emergency department.PDF [Dataset]. http://doi.org/10.3389/fpubh.2024.1352815.s001
    Explore at:
    pdfAvailable download formats
    Dataset updated
    May 22, 2024
    Dataset provided by
    Frontiers
    Authors
    Sofia Chaudhary; Kiesha Fraser Doh; Emilie Morris; Caroline Chivily; Donnetta S. Washington; Scott E. Gillepsie; Andrew Jergel; Sarah Lazarus; Angela Costa; Nathan Call; Jonathan Rupp; Harold K. Simon
    License

    Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
    License information was derived automatically

    Description

    BackgroundFirearm-related suicide is the second leading cause of pediatric firearm death. Lethal means counseling (LMC) can improve firearm safe-storage practices for families with youth at risk of suicide.ObjectivesThis study aims to evaluate the feasibility of pediatric emergency department (ED) behavioral mental health (BMH) specialists providing LMC to caregivers of youth presenting with BMH complaints and to test for changes in firearm safety practices, pre-post ED LMC intervention, as measures of preliminary efficacy.MethodsProspective pilot feasibility study of caregivers of youth presenting to a pediatric ED with BMH complaints. Caregivers completed an electronic survey regarding demographics and firearm safe-storage knowledge/practices followed by BMH specialist LMC. Firearm owners were offered a free lockbox and/or trigger lock. One-week follow-up surveys gathered self-reported data on firearm safety practices and intervention acceptability. One-month interviews with randomly sampled firearm owners collected additional firearm safety data. Primary outcomes were feasibility measures, including participant accrual/attrition and LMC intervention acceptability. Secondary outcomes included self-reported firearm safety practice changes. Feasibility benchmarks were manually tabulated, and Likert-scale acceptability responses were dichotomized to strongly agree/agree vs. neutral/disagree/strongly disagree. Descriptive statistics were used for univariate and paired data responses.ResultsIn total, 81 caregivers were approached; of which, 50 (81%) caregivers enrolled. A total of 44% reported having a firearm at home, 80% completed follow-up at 1- week. More than 80% affirmed that ED firearm safety education was useful and that the ED is an appropriate place for firearm safety discussions. In total, 58% of participants reported not having prior firearm safety education/counseling. Among firearm owners (n = 22), 18% reported rarely/never previously using a safe-storage device, and 59% of firearm owners requested safe storage devices.At 1-week follow-up (n = 40), a greater proportion of caregivers self-reported asking about firearms before their child visited other homes (+28%). Among firearm owners that completed follow-up (n = 19), 100% reported storing all firearms locked at 1-week (+23% post-intervention). In total, 10 caregivers reported temporarily/permanently removing firearms from the home.ConclusionIt is feasible to provide LMC in the pediatric ED via BMH specialists to families of high-risk youth. Caregivers were receptive to LMC and reported finding this intervention useful, acceptable, and appropriate. Additionally, LMC and device distribution led to reported changes in safe storage practices.

  10. age-period-cohort effects on the temporal trend mortality from male suicide...

    • zenodo.org
    Updated Apr 24, 2025
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Meira Karina Cardoso Meira; Meira Karina Cardoso Meira; Rodrigues Weverton Thiago da Silva; Rodrigues Weverton Thiago da Silva (2025). age-period-cohort effects on the temporal trend mortality from male suicide in Brazil from 1980 to 2019 [Dataset]. http://doi.org/10.5281/zenodo.7547810
    Explore at:
    Dataset updated
    Apr 24, 2025
    Dataset provided by
    Zenodohttp://zenodo.org/
    Authors
    Meira Karina Cardoso Meira; Meira Karina Cardoso Meira; Rodrigues Weverton Thiago da Silva; Rodrigues Weverton Thiago da Silva
    License

    Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
    License information was derived automatically

    Area covered
    Brazil
    Description

    The available files represent the records of deaths by suicide in men in Brazil and its major regions in the period from 1980 to 2019, in addition to the number of deaths after the correction process for the quality and coverage of deaths, for total suicides and suicides by weapon. of fire. The database for total and firearm suicides, represents the number of corrected deaths presented in age groups and periods grouped into five-year periods, which were used to carry out the analyzes of the effect of age, period and cohort, for total suicides and by weapon. of fire for Brazil and its great regions.

    .

  11. f

    Changes in suicide methods over time in Denmark by sex, 1995–2019.

    • plos.figshare.com
    xls
    Updated Dec 29, 2023
    Share
    FacebookFacebook
    TwitterTwitter
    Email
    Click to copy link
    Link copied
    Close
    Cite
    Agnieszka Konieczna; Christina Petrea Larsen; Sarah Grube Jakobsen; Taro Okuda; Karin Moriyama; Winibaldus Stefanus Mere; Erik Christiansen (2023). Changes in suicide methods over time in Denmark by sex, 1995–2019. [Dataset]. http://doi.org/10.1371/journal.pone.0296324.t002
    Explore at:
    xlsAvailable download formats
    Dataset updated
    Dec 29, 2023
    Dataset provided by
    PLOS ONE
    Authors
    Agnieszka Konieczna; Christina Petrea Larsen; Sarah Grube Jakobsen; Taro Okuda; Karin Moriyama; Winibaldus Stefanus Mere; Erik Christiansen
    License

    Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
    License information was derived automatically

    Area covered
    Denmark
    Description

    Changes in suicide methods over time in Denmark by sex, 1995–2019.

  12. Not seeing a result you expected?
    Learn how you can add new datasets to our index.

Share
FacebookFacebook
TwitterTwitter
Email
Click to copy link
Link copied
Close
Cite
The Associated Press (2025). Mass Killings in America, 2006 - present [Dataset]. https://data.world/associatedpress/mass-killings-public

Mass Killings in America, 2006 - present

Data from the AP-USA TODAY-Northeastern project tracking the killings of four or more victims from 2006-present

Explore at:
7 scholarly articles cite this dataset (View in Google Scholar)
zip, csvAvailable download formats
Dataset updated
Jul 17, 2025
Authors
The Associated Press
Time period covered
Jan 1, 2006 - Jul 4, 2025
Area covered
Description

THIS DATASET WAS LAST UPDATED AT 8:11 PM EASTERN ON JULY 16

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.

Search
Clear search
Close search
Google apps
Main menu