Table.

Key facts on included data sources for police violence in the USA

	Organisation type	Years of data available	Case definition	Data collection method	Percentage of cases missing race or ethnicity	Sources of bias from gold standard
Fatal Encounters	501(c)(3) non-profit	2005–19*†	People killed during encounters with the police	Open-source methodology: researchers collate news reports and public records requests	22%	Case definition; percentage missing in race or ethnicity
Mapping Police Violence	501(c)(3) non-profit research collaborative	2013–19*	Police killings	Open-source methodology: researchers collate news reports and public records requests	9%	Percentage missing in race or ethnicity
The Counted	Project of The Guardian newspaper	2015–16	People killed by the police and other law enforcement agencies	Open-source methodology: researchers collate news reports and public records requests	2%	Not applicable (gold standard)
National Vital Statistics System	Government system coordinated by the National Center for Health Statistics	1980–2018‡	Legal intervention ICD code as underlying cause of death (Y35.0–Y35.4, Y35.6–Y35.9, and Y89.0 in ICD-10, and E970–E977 in ICD-9§)	Death certificates: medical examiner or coroner determines cause of death	15%	Data collection method; percentage missing in race or ethnicity

ICD=International Classification of Diseases. GBD=Global Burden of Diseases, Injuries, and Risk Factors Study.

^*Data collection is ongoing; the last complete year of data at the time of this study was 2019.

^†Fatal Encounters includes data for 2000–04, which we chose to exclude due to concerns about their completeness (see appendix pp 6–7).

^‡The National Vital Statistics System existed before 1980; however, we limit our analyses to data from 1980 onwards to enable use of the time series produced by GBD.

^§See appendix pp 23–25 for full code names.