Data sources and inclusion rules

Where the records come from, how cases are identified and checked, and what the dataset covers.

Methods entries document how EWRL research is produced. Findings and conclusions appear in the Reports and Evidence Base collections.

What the dataset covers

The Edged-Weapon Response Lab dataset records fatal police encounters in the United States that involved an edged weapon, from January 2015 through December 2024. It currently holds 1,970 records. Each record represents one decedent and one fatal encounter; no incident in the dataset involved multiple decedents.

Source databases

Case identification begins with two publicly available databases maintained by independent organizations:

Washington Post Fatal Force records every person fatally shot by an on-duty police officer in the United States since 2015. The database is continuously updated and draws on news reporting, public records, and official data. (Washington Post, 2025)

Mapping Police Violence compiles fatal encounters with police from multiple independent sources, including media reports, legal settlements, and government records. (Mapping Police Violence, 2026)

The Lab does not republish these databases and does not alter their records. Readers who need case-level details should consult those sources directly.

How edged-weapon cases are identified

Each source database was filtered to the study period (January 1, 2015 – December 31, 2024) and then processed identically.

From the Washington Post (10,430 total fatalities in the study period):

Excluded as unarmed: 565 records
Excluded — weapon outside the edged-weapon definition: 6,859 records
Retained — explicitly coded as edged-weapon involved: 1,802 records
Individually reviewed — ambiguous or missing weapon classification: 1,204 records, yielding 180 additional qualifying cases
Washington Post qualifying records: 1,982

From Mapping Police Violence (11,523 total in the study period):

Same procedure applied; 26 additional cases verified from the ambiguous pool
Mapping Police Violence qualifying records: 1,971

Individual review of ambiguous records uses the decedent’s name, city, state, and open-source reporting to confirm or exclude the case.

Deduplication

The two source lists were merged (N = 3,953 combined qualifying records) and deduplicated on decedent name, date, and location, reducing the combined list to 1,996 unique cases.

A case-by-case verification pass then removed 26 records that did not meet the operational definition on closer examination — for example, a knife-armed subject who drove a vehicle at officers, a subject who had dropped the weapon before the fatal sequence, or a subject killed by a less-lethal deployment rather than gunfire. One further case in which the discharge was unintentional was also removed.

Final analytic sample: 1,970 records.

Operational definition

An encounter qualifies if the decedent’s conduct with an edged or improvised sharp weapon — not any other weapon also present — precipitated the first police firearm discharge.

Situation	Rule
Edged weapon + firearm both present	Retained if edged-weapon conduct precipitated the shooting; excluded if firearm conduct did
Vehicle also involved	Excluded if the decedent’s use of the vehicle precipitated the shooting, regardless of edged weapon present
Subject complied or surrendered	Excluded if the weapon was dropped or surrendered before the fatal sequence began

Exclusion criteria

A case is excluded if any of the following applies:

The decedent was unarmed
The decedent was armed exclusively with a non-edged weapon
The decedent’s use of a vehicle, not the edged weapon, precipitated the shooting
The decedent had dropped or surrendered the weapon before the fatal sequence
The decedent was killed by a less-lethal deployment rather than a firearm discharge
The discharge was accidental or unintentional
The encounter involved an off-duty officer acting in a personal capacity rather than a law enforcement one

Three pairs of same-date, same-agency incidents

Three pairs of records in the dataset share a date and agency but involve separate decedents at distinct encounters. These were retained as separate records after individual verification.

Snapshots and versioning

The dataset is versioned. Each published report names the snapshot it draws on, and no snapshot is edited after publication. Changes across snapshots — additions, corrections, removals — are recorded in the version history.

References

Mapping Police Violence. (2026). Mapping Police Violence database [Data set]. Retrieved March 4, 2026, from https://mappingpoliceviolence.org

Washington Post. (2025). Fatal Force database [Data set]. Retrieved August 11, 2025, from https://github.com/washingtonpost/data-police-shootings

How to cite

Edged-Weapon Response Lab. (2026). Data sources and inclusion rules. In EWRL Methods Documentation (Version 1.0). https://droptheknife.org/methods/data-sources