As the nation reels from a series of high-profile fatal shootings of black men by police officers, many have decried the lack of readily available data on how racial bias factors into American policing. But while it’s true that there is no adequate federal database of fatal police shootings (F.B.I. director James Comey has described the lack of data as “embarrassing and ridiculous”), there exists a wealth of academic research, official and media investigations, and court rulings on the topic of race and law enforcement.

The Hive has collected 18 such findings below. This list is not exhaustive, and does not purport to comment on the work of all police officers. It is, rather, merely a digest of the information available at present. Sometimes, studies and investigations reveal evidence of intentional bias; other studies point to broader societal and institutional factors that lead to implicit bias. Taken together, the research paints a picture of a nation where a citizen’s race may well affect their experience with police—whether an encounter ends with a traffic stop, the use of police force, or a fatal shooting.

POLICE KILLINGS OF UNARMED AMERICANS

1. A study by a University of California, Davis professor found “evidence of a significant bias in the killing of unarmed black Americans relative to unarmed white Americans, in that the probability of being black, unarmed, and shot by police is about 3.49 times the probability of being white, unarmed, and shot by police on average.” Additionally, the analysis found that “there is no relationship between county-level racial bias in police shootings and crime rates (even race-specific crime rates), meaning that the racial bias observed in police shootings in this data set is not explainable as a response to local-level crime rates.”

2. An independent analysis of Washington Post data on police killings found that, “when factoring in threat level, black Americans who are fatally shot by police are, in fact, less likely to be posing an imminent lethal threat to the officers at the moment they are killed than white Americans fatally shot by police.” According to one of the report’s authors, “The only thing that was significant in predicting whether someone shot and killed by police was unarmed was whether or not they were black. . . . Crime variables did not matter in terms of predicting whether the person killed was unarmed.”

3. An analysis of the use of lethal force by police in 2015 found no correlation between the level of violent crime in an area and that area’s police killing rates. That finding, by the Black Lives Matter–affiliated group Mapping Police Violence, disputes the idea that police only kill people when operating under intense conditions in high-crime areas. Mapping Police Violence found that fewer than one in three black people killed by police in 2016 were suspected of a violent crime or armed.

HOW POLICE DETERMINE WHOM TO STOP

4. A report by retired federal and state judges tasked by the San Francisco district attorney’s office to examine police practices in San Francisco found “racial disparities regarding S.F.P.D. stops, searches, and arrests, particularly for Black people.” The judges, working with experts from five law schools, including Stanford Law School, found that “the disparity gap in arrests was found to have been increasing in San Francisco.” (Officers in San Francisco were previously revealed to have traded racist and homophobic text messages, and those working in the prison system had reportedly staged and placed bets on inmate fights.)