THIS DATASET WAS LAST UPDATED AT 8:11 PM EASTERN ON SEPT. 10

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.

This dataset was retrieved from the U.S. Department of Justice Federal Bureau of Investigation Criminal Justice Information Services Division website on February 29, 2008. "This table provides arrest data for 29 separate UCR offenses for each state for 2006. The table provides arrests of juveniles (persons under the age of 18)", by class of crime. "The FBI collects these data through the Uniform Crime Reporting (UCR) Program". Please see the Data Declaration for further information on the data set. Values of -1 represent no value.

This dataset explores the USDA national school lunch program by reporting the number of children participating at two points in time (Feb. 2007 and Jan. and Feb. 2008) and the percent change from 2007 to 2008. *Participation data are based on average daily meals adjusted by an attendance factor of 0.927. Data for January and February 2008 are preliminary and are subject to significant change; all data are subject to revision.

This dataset lists the number of well known school shootings by state. Some states have had more incidents than others. School shooting is a term popularized in American and Canadian media to describe gun violence at educational institutions, especially the mass murder or spree killing of people connected with an institution. A school shooting can be perpetrated by one or more students, expelled students, alumni, faculty members, or outsiders. Unlike acts of revenge against specific people, school shootings usually involve multiple intended or actual victims, often randomly targeted. Source: Wikipedia section on school shootings http://en.wikipedia.org/wiki/School_shootings#List_of_school_shootings

This dataset explores the time between tpr and finalization for fiscal year 2006 (from October 1, 2005 to September 30, 2006) from the Department of Health and Human Services - Administration for children and families - Children's Bureau.

This dataset explores Early Care and Education Funding: Head Start Allocation and State-Funded Prekindergarten Participation. This data is state level and expresses the participation per state. Head Start and Early Head Start are comprehensive child development programs that serve children from birth to age 5, their families, and pregnant women. The overall goal of these programs is to increase the school readiness of young children in families earning low incomes. The Head Start program delivers comprehensive services including: education, health, nutrition, screening for developmental delays, and a variety of social services, if the family needs them. The program is designed to meet the social, emotional, physical and cognitive development of children. This data is from Latest Data: Fiscal Year 2004 (Head Start) and School Year 2002-2003 (State Funded Prekindergarten). This data is from National Child Care Information Center. Refer to NCCIC Child Care Database for detailed state information (http://nccic.org/IMS/Results.asp). Compiled by: National Association of Child Care Resources and Referral Agencies (http://www.naccrra.org/randd/head_start/expenditure.php)

This dataset was collected from the Children's Defense Fund website. The data come from the "Protect Children, Not Guns" Reports from years 2007, 2004 and 2000. They include data on deaths of children from firearms due to homicide, suicide, accident, and undetermined intent from 1996 to 2004 by state. Sources: U.S. Department of Health and Human Services, National Center for Health Statistics, Table III: Deaths from # selected causes, and U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, WISQARS, at http://www.cdc.gov/ncipc/wisqars/ [2001]. Calculations by the Childrens Defense Fund.

This dataset depicts the number of adopted children during the October 1, 2004 - September 30, 2005 time period. The numbers are categorized and broken down by state. The male and female figures are the percentage that each makes up of the total number of those adopted. This data was collected at: http://www.acf.hhs.gov/programs/cb/stats_research/afcars/statistics/gender_tbl1_2005.htm Access Date November 13, 2007.

This dataset explores the prior relationship of adoptive parents to their adoptee children during fiscal year 2006 (from October 1, 2005 to September 30, 2006). *The data from Maryland, Nebraska, New York, Ohio, Rhode Island and Washington was questionable due to the large percentage of missing data. *Iowa does not track non-welfare stepparent adoptions. Law defines relative as the fourth degree of consanguinity. *Nebraska includes great aunt/uncle, great grandparent, great great great grandparent, great great aunt/uncle, great great great grandparent, great great great aunt/uncle, adoptive sibling, biological sibling, first and second cousins, grandparent, parent-in-law, aunt/uncle. Fictive kin (ie. Godparents) are not included.

This dataset explores the gender of public agency children adopted in fiscal year 2006 by state in the USA.

This dataset explores the cash received for school lunches by state from the national school lunch program for the years 2003- 2007. Payments to State agencies are based on per meal rates which are adjusted annually to offset changes in food prices. Administrative costs are not included. Department of Defense activity represents children of armed forces personnel attending schools overseas. Cash payments include the costs of snacks served under the National School Lunch Program as well as lunches. Data are subject to revision.

This dataset explores Foster Care FY2000 - FY2005 Entries, Exits, and Numbers of Children In Care on the Last Day of Each Federal Fiscal Year. NOTE: This table reflects State data submitted to the Children's Bureau as of March 2007. The table does not include any estimates for individual States. Jurisdictions with insufficient data ("NA") are not included in the total for that year. Pre-2003 Nevada data were generated from various sources, rather than from a statewide child welfare system. NOTE: Ideally, if the number of children in the "in care" count declines, as it did during this period, the number of exits should consistently be greater than the number of entries in that year. However, this does not occur with these data. Underreporting of foster care exits by some States is the major reason for this data quality issue.

This dataset looks at age and juvenile offender status as a means of restricting the purchase and possession of firearms in the USA as of 12.31.2005. This data displays the minimum age you must be to purchase/possess a handgun or a long gun in every state in the USA. It also displays if a state restricts juvenile offenders from purchasing/possessing a firearm, handguns or long guns. Also provided in the data is the statute within the States legislation that states the firearm purchase/possession restriction. Handgun: A firearm that has a short stock and is designed to be held and fired by the use of a single hand, such as a pistol or revolver. Long gun: A firearm with a barrel extended to around 30 inches to improve accuracy and range, and commonly with a shoulder butt, designed to be fired with two hands, such as a rifle or shotgun. This data comes from Survey of State Procedures Related to Firearm Transfers, 2005. The Survey provides an overview of the firearm check procedures in each State and State interaction with the National Instant Criminal Background Check System (NICS) operated by the FBI. The report summarizes issues about State procedures, including persons prohibited from purchasing firearms, restoration of rights of purchase to prohibited persons, permits, prohibited firearms, waiting periods, fees, and appeals. Supplemental tables contain data on 2005 applications to purchase firearms and rejections, as well as tabular presentations of State-by-State responses. This is one of a series of reports published from the BJS Firearm Inquiry Statistics (FIST) project, managed under the BJS National Criminal History Improvement Program (NCHIP). This is a web only document.

This dataset explores the child's finalization age at adoption by state. The ages are grouped as under 1, 1-5, 6-10, 11-15, 16-18, 19 and older. This dataset is from October 2005 - September 2006 (Fiscal year 2006).

This dataset explores what child care providers earn for 2005 and 2006. The BLS defines child care workers as those who attend to children at schools, businesses, private households, and child care institutions and perform a variety of tasks, such as dressing, feeding, bathing, and overseeing play. It is important to note that some family child care providers are excluded in the numbers because they are self-employed and report their income differently. The definition also excludes preschool teachers and teacher assistants. All data obtained from the 2005 and 2006 Occupational Employment Statistics Survey, Bureau of Labor Statistics, U. S. Department of Labor Compiled by the National Association of Child Care Resource and Referral Agencies.

This data explores the U.S. Department of Health and Human Services (DHHS) Administration for Children and Families Administration on Children, Youth and Families Children's Bureau Adoption of Children with Public Child Welfare Agency Involvement by State for Fiscal Years 1995 - 2006. For Fiscal Years 1995 - 1997, The data for FY 1995-FY 1997 were reported by States to set baselines for the Adoption Incentive Program. They came from a variety of sources including the Adoption and Foster Care Analysis and Reporting System (AFCARS), court records, file reviews and legacy information systems. For Fiscal Years 1998 - 2006, Unless otherwise noted, the data come from the AFCARS adoption database. Because AFCARS adoption data are being continuously updated and cleaned, the numbers reported here may differ from data reported elsewhere. In addition, data reported for the Adoption Incentive Program will differ from these data because adoptions reported for that program are identified through a different AFCARS data element and must qualify in other ways to be counted toward the award of incentive funds. Counts include adoptions reported as of 6/1/2005. Where appropriate, AFCARS data have been adjusted for duplication.

This dataset displays public elementary and secondary schools throughout the country that are either single-sex schools or offer single-sex classes for the 2008-2009 school year. For the 2008-2009 school year, there are at least 392 public schools in the United States offering single-sex educational opportunities. Most of those schools are COED schools which offer single-sex CLASSROOMS, but which retain at least some coed activities. In some cases, the only coed activities are lunch and one or two electives, so the distinction between a single-sex school, and a coed school with single-sex classrooms, can become a semantic quibble. From March 2002 through July 2007, we tried to make a distinction between single-sex schools, on the one hand, and coed schools with single-sex classes, on the other hand. We listed single-sex schools on one web page, while coed schools with single-sex classes were listed on a separate web page. As it became increasingly obvious that the distinction was often arbitrary, we decided in August 2007 to begin listing all public schools offering single-sex classrooms on the same web page, which is this page. By our count, 97 of the 392 schools below qualify as single-sex schools, meaning that students attending any of those 97 schools have all their school activities -- including lunch and all electives -- in a setting which is all-boys or all-girls. Most of those 97 schools are single-sex campuses, such as the The Ann Richards School for Young Women which opened in Austin, Texas in August 2007. Note: Schools which offer single-sex classes only in physical education and/or health and/or sex education are NOT listed here. In addition, correctional schools for adjudicated delinquent juveniles are not listed here.

This dataset was retrieved from the U.S. Department of Justice Federal Bureau of Investigation Criminal Justice Information Services Division website on February 29, 2008. "This table provides the estimated number of offenses and the actual number of offenses reported in the Metropolitan Statistical Areas (MSA), cities outside metropolitan areas, and nonmetropolitan counties, and the rate (per 100,000 inhabitants) for each grouping, and the estimated population for each state" however to simplify the dataset, I only included the state total and the rate for each state. Data for Puerto Rico was not included. "The FBI collects these data through the Uniform Crime Reporting (UCR) Program". Please see the Data Declaration for further information on the data set. Values of -1 represent no value.

Diseases of the Respiratory System: Effects are generally irritation and reduced lung function with increased incidence of respiratory disease, especially in more susceptible members of the population such as young children, the elderly and asthmatics. Diseases of the Respiratory System includes: ICD-9 BTL codes B31-B32, ICD-9 code CH08 for some ex-USSR countries, ICD-9 code C052 for China, ICD-10 codes J00-J99, European mortality indicator database (HFA-MDB), available at www.euro.who.int, for missing figures for some european countries: indicator "3250 Deaths, Diseases of the Respiratory System" The original dataset uses a value of -9999 to indicate no data available, i have substituted a value of 0. Online resource: http://geodata.grid.unep.ch URL original source: http://www3.who.int/whosis/mort/text/download.cfm?path=whosis,evidence,whsa,mort_download&language=english

Ozone (O3) is a photochemical oxidant and the major component of smog. While O3 in the upper atmosphere is beneficial to life by shielding the earth from harmful ultraviolet radiation from the sun, high concentrations of O3 at ground level are a major health and environmental concern. The reactivity of O3 causes health problems because it damages lung tissue, reduces lung function and sensitizes the lungs to other irritants. Scientific evidence indicates that ambient levels of O3 not only affect people with impaired respiratory systems, such as asthmatics, but healthy adults and children as well. Title 40, Part 50 of the Code of the Federal Regulations lists the ambient air quality standards for ozone. Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS) Originator: Federal Highway Administration, Office of Planning, HEPP-1 Publication_Date: 2006 Title: Non-Attainment Areas: Ozone Geospatial_Data_Presentation_Form: vector digital data Publication_Information: Publication_Place: Washington, DC Publisher: Research and Innovative Technology Administration's Bureau of Transportation Statistics (RITA/BTS) Online_Linkage: Abstract: Non-attainment and maintenance areas for the United States and its territories. For more detailed information on this dataset, see the Overview Description in the Entity Attribute section of this document. Purpose: To establish the spatial boundaries of each nonattainment and maintenance area.