Data and Methodology
Data last updated 01/31/2023
We encourage users to review the full methodology which is accessible here or via web. Our methodology was last updated on Oct 3, 2022.
We have included extracts to summarize our methodology below:
MPV Definition of Police Violence
Any incident where a law enforcement officer (off-duty or on-duty) applies, on a civilian, lethal force resulting in the civilian being killed whether it is considered “justified” or “unjustified” by the U.S. Criminal Legal System.
A few disclaimers:
- Vehicular Force. Cases when vehicles are used as a form of lethal force or cases when the vehicle is deliberately driven in a manner that is directed at civilian(s) and/or the vehicle the civilian(s) are in (e.g. PIT maneuvers) are included. However, civilians who were killed by a civilian driver or crashed without being hit directly by police during a police pursuit are not coded as incidents of police violence. We have started to internally track Vehicular Chase incidents and will continue to collect and analyze that data.
- Suicide by Cop. Cases where a civilian is killed by a law enforcement officer when they’re labeled as having a mental health crisis or in a state where they’re characterized as “Suicidal” (sometimes referred to as “Suicide by Cop”) are included as incidents of police violence.
- Possible Suicide. We have started to collect incidents where a reported death is characterized as a “suicide” and provide it to another team to separately review the specifics.
- Off-Duty. Cases where a law enforcement officer kills a civilian while they’re “off-duty” is considered an incident of police violence. Additionally, it is worth noting that 97% of the incidents in MPV occurred while a police officer was acting in a law enforcement capacity. Thus, while MPV does include data on off-duty officers, it does not include killings by vigilantes or security guards who are not off-duty police officers. This is a gap in the field that should be further investigated, especially at the intersection of “Stand Your Ground Laws.”
Mapping Police Violence sources data from a number of sources. While we strive to employ official data sources from local and state government agencies, we believe it is important to continue collecting data from publicly-accessible media sources. This allows us to identify gaps in government data, and further triangulate and validate the data.
After conducting an internal comparison of different news aggregators, we decided to use Google News as our primary method for detecting news media mentions of police violence. We are continuing to develop and improve our own automated systems to filter out irrelevant news articles, maximize the comprehensiveness of the articles we do detect, and reduce potential human coding errors.
The steps we now follow to collect data are:
Record potential news media mentions of police violence.
- Google News feeds provide a near real-time, continuous stream of potentially relevant news media articles.
- Our custom algorithms perform additional filtering of articles provided by Google that are obviously unrelated to police violence in the US.
Researchers review articles to determine if the events reported qualify as incidents of police violence.
Researchers create a draft entry of the incident.
They record information about the demographics of the civilian(s) killed and officers involved, as well as the context and circumstances of the incident.
Second-stage review of draft entries.
Another researcher (a different individual from the one who created the draft entry) reviews the draft entry and corrects and updates any incorrect, missing, or out-of-date information. Once the second-stage review is complete, the incident is added to the public MPV database.
Researchers perform periodic validation of incident information.
We match our published incidents with following data sources:
- Fatal Encounters
- Fatal Force/The Washington Post
- Official Government Data Sources (e.g. NVSS, California DOJ, etc.)
Researchers perform periodic review to fill in potentially missing data.
Cadence of updates to the live tracker
It is important to note that incidents are reviewed at different times. This can be for several reasons, including delays between an incident occurring and being mentioned in the news, or second reviewers flagging incidents for further review due to possible reliability concerns. Thus, the date presented on the live tracker does not reflect the most recent internally reviewed incident. Our research and product team do their best to keep the live tracker as comprehensive and up-to-date as possible.
A note on 2022 data.
Since transitioning and revamping our methodology, there will be a significant delay in the publishing of incidents due to the complete revamp, development, and improvement of the platform and coding process. Further discussion about the revamp can be found in the full methodology.
We believe data quality and accuracy should supersede speed of publishing given the sensitivity of the data.
When we publish incident data
Given that initial news reporting on incidents tend to be police-centric and significantly differ in narrative and details, we believe there is a responsibility to allow for a sufficient amount of time to pass prior to publishing incidents that may misrepresent the true details of the incident. This is both critical for data integrity and to honor the families and loved ones of victims to not present inaccurate, distorted, or false accounting of details.
The same data limitations noted by FE also apply to MPV given the similarities of how the data is sourced and generated.
Additional disclaimers and clarifications are noted below:
- Date of incident versus date of death. We use the date of police lethal action as the incident of police violence even if the victim passes at a later date due to the injuries.
- Victim passes following incident. If the victim passes as a result of lethal actions which led to the victim’s death at a later time such as en route to the hospital or at the hospital, it is still included (e.g., Eric Garner).
- Agency: Unknown Jurisdiction or Beyond Jurisdiction. In cases where the law enforcement officer agency is different from the incident of the police killing, the agency of the officer is used despite it being beyond the officer's jurisdiction.
- Data on officers and case outcomes. MPV captures information on all involved officers in each case (both the officers who killed the person and any other officers on the scene during the use of deadly force), including the name and race of each officer, any prior deadly force incidents involving that officer that have been reported by the media, and whether the case resulted in any administrative discipline, civil suits and/or misconduct settlements. Additionally, MPV tracks cases where officers have been charged with a crime related to an incident of fatal police violence. This data is collected during ongoing monitoring of media reports related to each case in our database.
- Cross-referencing data between sources to update, validate, and detect errors.
- Weekly review and cleaning.
A note on the police violence data sources and replication
We posit that the data collected, coded, and made available belongs to the public. It is not and should not be owned by any platform. We encourage communities, organizations, and other individuals to develop their own databases. This only strengthens the integrity and validity of the data by allowing us to study the differences across datasets and improve data collection efforts when there are attempts to harmonize and study the data. For example, a recent study has found that while the three major police violence datasets are similar, they have started to become more dissimilar over recent years (Comer and Ingram, 2022).
Thus, we are always open to partnerships and collaborations to improve the methodology and/or share best practices. We center collaboration and co-creation over ego, which can be a departure from orthodox academic norms and culture.
We want to acknowledge and thank Samuel Sinyangwe, a Campaign Zero co-founder for leading this work and the development of the initial methodology. We also want to acknowledge and thank D. Brian Burghart, founder of Fatal Encounters, who advised the initial development of the project and continues to advise and collaborate on the methodology.
Our previous methodology primarily sourced data from Fatal Encounters, The Washington Post, publicly-accessible media sources, and official data sources from local and state agencies required to report this data (e.g., California Department of Justice).
We are working to make our methodology more rigorous and efficient by partnering with different organizations and automating how we collect and validate data. We’re constantly striving to improve our methods and systems. Please contact us if you have any suggestions or would like to partner in any way.