Methodology

Updated: May 2022

Firearm Deaths

Fatal injury data come from the Centers for Disease Control and Prevention (CDC)’s National Vital Statistics System (NVSS). The CDC compiles this data from death certificates, which are provided by vital registration systems from state and local jurisdictions.

EveryStat uses CDC data from the Wide-ranging ONline Data for Epidemiologic Research (WONDER).

Version: The most recent data from the CDC published on EveryStat is for 2020. Unless noted, and in order to account for normal fluctuations that occur between years, deaths are a five-year average of the years 2016 to 2020.

 

Intimate Partner Homicides

Statistics of intimate partner homicides (IPHs) are based on data from the CDC’s National Violent Death Reporting System (NVDRS). This is one of the few sources of homicide data that includes information about the relationship between the victim and offender. Participation in NVDRS has been growing over time: in 2019, 43 states and the District of Columbia submitted data for at least some counties. For states with partial NVDRS coverage, IPH rates were applied to state population totals to estimate the number of deaths for the entire state. For non-participating states, national rates were applied to state population totals to estimate the IPH deaths. 

Version: The most recent data from NVDRS published on EveryStat is for 2019. Race and ethnicity data represent two years, 2018 and 2019, in order to have sufficient data for estimates.

 

Firearm Homicides and Fatal Shootings by Police

While the CDC is considered to be the most comprehensive source for data on fatal firearm injuries, research shows its data on “legal intervention” (i.e., shootings by police or other law-enforcing agents) are greatly underreported and are often misclassified as homicides. To account for this, with the exception of the “Gun Deaths by Intent” pie chart, data on firearm homicides have been combined with shootings by police.

To highlight the extent of this problem, the “Gun Deaths by Intent” pie chart includes a note with data on fatal shootings by police from the Mapping Police Violence database.

Version: The most recent data from the CDC published on EveryStat is for 2020. Unless noted, and in order to account for normal fluctuations that occur between years, deaths are a five-year average of the years 2016 to 2020. The most recent data from Mapping Police Violence published on EveryStat are from 2021. In order to account for normal fluctuations that occur between years, deaths are a five-year average of the years 2017 to 2021.

 

Transgender Homicides

Data on the homicide of transgender and gender nonconforming Americans are gathered by Everytown for Gun Safety through media reports. In this analysis, “transgender” and “gender nonconforming” identities include any victim who lived or identified as a gender different from that which was ascribed to them at birth.

Version: The most recent data from the Everytown Transgender Homicide Tracker published on EveryStat is updated in real time.

 

Nonfatal Firearm Injuries

Data on nonfatal firearm injuries are based on the Agency for Healthcare Research and Quality’s (AHRQ) Healthcare Cost and Utilization Project (HCUP) surveys of hospital discharges.

Everytown has worked with Ted R. Miller and the Pacific Institute for Research and Evaluation (PIRE), using multiple data sets, to calculate nonfatal injuries:

  1. Restricted-access National Emergency Department Sample (NEDS) of emergency department discharges.
  2. Restricted-access National (Nationwide) Inpatient Sample (NIS) of inpatient hospital admissions.
  3. State Emergency Department Databases (SEDD), including both restricted access and publicly available data through hcup.net.
  4. State Inpatient Databases (SID), including both restricted access and publicly available data through hcup.net.

Note that because of rounding and analysis done to create state-level estimates, the sum of the state estimates does not equal the national total. For further analysis on nonfatal injuries, please see the report. For further information on the methodology behind the nonfatal firearm injuries count, please see the Methodological Note

Version: The most recent data on nonfatal injuries published on EveryStat are from 2017, the most recent state-level estimates available from researchers.

 

Economic Cost of Gun Violence

Data on the costs of gun violence are constructed from the calculation:

Total cost = cost per nonfatal injury or death x number of injuries and deaths

Costs per fatal and nonfatal injury are based on research by Ted R. Miller and PIRE. Costs to society include out-of-pocket payments for medical care, mental healthcare, emergency transport, police response, criminal justice and incarceration, employer costs, work loss for victims and perpetrators, and lost quality of life. Costs to taxpayers include government payments for medical care, mental healthcare, emergency transport, police response, criminal justice and incarceration, Medicaid, and Social Security Insurance payments. Further methodology of these unit costs is available from the Methodological Note.

The number of nonfatal firearm injuries used to calculate the total cost of gun violence for states was estimated from the 2017 Healthcare Cost and Utilization Project (HCUP) data on hospital emergency department and inpatient files (see Methodological Note). The number of firearm deaths used to calculate the total cost of gun violence for states was as per the CDC WONDER for 2018. 

Version: The most recent data on costs of gun violence published on EveryStat are in 2018 US dollars, based on 2018 firearm deaths and 2017 firearm nonfatal injuries.

 

Congressional District Analysis

Everytown calculated suicide by congressional district using county-level data on the number of suicides and firearm suicides obtained from CDC WONDER, Underlying Cause of Death, combined with demographic data from the US Census Bureau. Allocation of counts from the county to the congressional district and calculation of rates for the congressional district were based on the methods from the American Cancer Society and published on the CDC website for calculation of congressional district cancer mortality. Counts of suicides and firearm suicides for the congressional districts were calculated by weighting county counts by the proportion of the county population allocated to the congressional district for that population group. The weighted counts were then summed over the counties in the congressional district. For further information, please see the Methods Note.

Version: The most recent data on firearm suicides by congressional district published on EveryStat are five-year averages for the years 2014 to 2018 using the district boundaries for the 116th Congress (2019 to 2020).

 

Population Denominators

  • For national, state, and county-level deaths, population denominators are from CDC’s WONDER according to its bridged race and ethnicity categories.
  • For nonfatal injuries, population denominators are provided by HCUP.
  • For congressional district data and fatal shootings by police, population denominators are from either the Census (including midyear estimates) or the American Community Survey, both accessible through https://data.census.gov/.

Suppressed, Unreliable, and Missing Data

Updated: May 2022

In order to protect individual identities, the CDC and AHRQ do not report data when the number of deaths or nonfatal injuries is fewer than or equal to 10 for any subnational estimates. For the calculation of percentages, when the numerator was fewer than 10, this is indicated as less than 5% or less than 1%. Further, the CDC considers population rates unreliable (large coefficients of variation) when the number of deaths or nonfatal injuries is fewer than or equal to 20. Data that are suppressed or considered unreliable have not been included in EveryStat.

Demographics

Updated: May 2022

Racial and ethnic categories in EveryStat are as defined by the CDC and considered “bridged race.” EveryStat contains five separate, mutually exclusive racial and ethnic categories.

American Indian = American Indian / Alaskan Native, non-Latinx

Asian = Asian / Pacific Islander, non-Latinx

Black = Black, non-Latinx

Latinx = American Indian / Alaskan Native Latinx + Asian / Pacific Islander Latinx + Black Latinx + white Latinx

White = white, non-Latinx

Children and teens are defined as individuals between the ages of 0 and 19 years. In statistics regarding the “leading causes of death,” however, children and teens are defined as those between the ages of 1 and 19. This distinction is made because the leading causes of death for newborns and infants less than 1 year of age are considerably different from those 1 year and older.

Analysis and Calculation

Updated: May 2022

Crude rate per 100,000 people = cases / population x 100,000

Crude rates per 100,000 people were calculated by dividing the number of cases by the population denominator and multiplying by 100,000.

Age-adjusted rates per 100,000 people

Age-adjusted rates per 100,000 people were obtained directly from the CDC and not calculated by Everytown.

Disparity ratio = rate of population A (higher rate) / rate of population B (lower rate)

To compare the rate at which a given outcome affects two different groups, a disparity ratio was used. For example, a disparity ratio was used to calculate the following: Black women are two times as likely as white women to be fatally shot by an intimate partner.

Percent change = (new value – previous value) / previous value

Percent change is used to compare new values to previous values. This formula is used when looking at the percentage increase or decrease.

Ranking

Rankings are based on all 50 states and Washington, DC, with 1st being the highest and 51st being the lowest. Firearm deaths are based on age-adjusted rates. Nonfatal injury rankings are based on crude rates. Economic cost rankings are based on the average societal per-person cost.

Hours between gun suicide deaths = 24/average daily gun deaths

The number of hours between gun suicide deaths was calculated by dividing 24 (i.e., the number of hours in a day) by the average number of gun deaths each day. The daily average gun suicide deaths was calculated by dividing the yearly average by 365.25 days, which accounts for leap years. Averages are based on five years of most recent available data from the CDC: 2016–2020. Hours were converted to minutes if the result was less than one hour, or converted to days if the number of hours was greater than 72 hours.