How police respond
to edged-weapon
critical incidents
Independent applied research examining the full course of edged-weapon critical incidents—from call-taking and officer arrival through tactical decision-making, intervention, medical response, investigation, review, and litigation.
- 1,970
- People Killed by Police
- 61.2%
- Mental Illness
- 50
- Jurisdictions
- 6 feet
- Reported Distance
In edged-weapon critical incidents, 2015–2024
Decedents with reported, suspected, or documented mental illness
49 states and the District of Columbia
Average recorded distance at firearm discharge
The critical incident lifecycle
The Lab organises research around the four phases of a critical incident.
Stage 1
Pre-Incident & Dispatch
Circumstances before police arrive, and how the call is taken and dispatched.
- Pre-incident circumstances
- Call-taking and dispatch
Stage 2
Arrival & Approach
What officers find on arrival and how the encounter develops toward contact.
- Officer arrival
- Subject behaviour
- Civilian risk
Stage 3
Encounter & Intervention
How the encounter develops once contact is established and decisions about intervention are made.
- Communication
- Containment
- Tactical decision-making
- Less-lethal and lethal intervention
Stage 4
Post-Incident & Analysis
What follows the encounter and how the incident is examined, reviewed, and understood.
- Medical response
- Investigation
- Review
- Litigation
- Policy implications
Explore the research
The Lab reports what the evidence supports, where it is uncertain, and what remains unknown.
Field Guide
New to the subject? Start here with guided topics and plain-language orientation.
The Field Guide introduces the major issues that shape edged-weapon critical incidents, explains how they connect across the incident lifecycle, and directs readers to the deeper research behind each topic.
Browse the research collection
Reports
Original versioned research based on EWRL data, available as a web page, Markdown, and PDF.
Evidence Base
Research on police intervention options—tactics, technology, and the evidence behind each.
Law & Policy
Case law and policy backgrounders, dated and tagged by jurisdiction and topic.
Bulletins
Concise synthesis connecting research, law and policy, and field practice across the incident lifecycle.
Annotated Bibliography
Annotated citations of leading research with DOI links, keyword tags, and summaries.
Table of Authorities
Cases, statutes, and constitutional provisions cited across EWRL research, with briefs and cross-references.
Who We Are
Independent by design
Our research and editorial conclusions are not directed by law-enforcement agencies, government bodies, advocacy organizations, litigation parties, or commercial entities.
- Analysis begins without a presumption that police conduct was justified or unjustified.
- Conclusions are based on available evidence, applicable research, and the relevant legal framework.
- Material uncertainty, competing evidence, and significant limitations are identified where possible.
How We Work
Evidence over opinion
We bring together data, research, legal authority, and documented incident evidence to support informed, defensible decisions and better outcomes.
- Legal, scientific, and tactical claims are limited to what the underlying authorities and research support.
- We use precise, descriptive language and avoid terms that unnecessarily assign motive, blame, or legal significance.
- Where the evidence does not permit a reliable conclusion, the Lab says so.
Common questions
Answers to common questions about the Lab, its data, and use of its research.
Who funds the Edged-Weapon Response Lab?
EWRL is independently funded. We do not accept funding from law-enforcement agencies, government bodies, advocacy organizations, litigation parties, or commercial entities with a financial interest in our conclusions. A full funding disclosure is available on our Independence & Disclosures page.
Is the underlying data available for download?
Aggregate, suppressed public data are available through the Data Explorer. Case-level data are not published. Researchers seeking access to underlying data for academic purposes should contact us to discuss a data-sharing agreement.
How do I cite Lab research?
Each report and intervention entry includes a suggested citation. In general: Edged-Weapon Response Lab. (year). Title. In Collection (Version x.x). https://droptheknife.org/… Reports are versioned — please cite the version you consulted.
Does the Lab take positions on individual incidents or cases?
No. EWRL does not comment on pending litigation, specific officer conduct determinations, or individual use-of-force incidents. Our research characterizes patterns across many incidents and the legal and tactical frameworks that apply to them.
Can I use Lab research in litigation or expert testimony?
EWRL research is published for public use and may be cited in legal proceedings. The Lab does not provide expert witnesses, litigation consulting, or case-specific analysis. Attorneys seeking general information about our methodology or data are welcome to contact us.
How often is the data updated?
Preliminary data are published quarterly and are updated annually. Each data snapshot is versioned and timestamped; reports cite the snapshot they were produced from. Prior snapshots are retained so that published research remains reproducible.
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Questions, corrections, or feedback?
The Lab welcomes feedback, corrections, and questions from researchers, practitioners, attorneys, and journalists.
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