(David McNew/Getty Images)
Opinion writer

Last September, I put up a post listing more than 120 studies demonstrating racial bias in the criminal-justice system. The studies covered nearly every nook and cranny of our carceral system — from police to prosecutors to prisons; from misdemeanor offenses to the death penalty; from sentencing to parole; and from youth offenses to plea bargaining to clemency. The post also included nine studies I could find that suggested racial bias was not a factor in some part of the criminal-justice system,

I also asked readers to send me any studies I missed, and I promised that I’d keep the list up to date as new studies came along. So here is our first update. I’ll both list the new studies here, and add them to the master list. As before, if you know of something I’ve missed or are aware of a forthcoming study, please let me know via email.

  • In March of 2019, researchers compiled and analyzed data from more than 100 million traffic stops in the United States. What they found: Police were more likely to pull over black drivers. The researchers were able to confirm racial bias by measuring daytime stops against nighttime stops, when darkness would make it more difficult to ascertain a driver’s race. As with previous studies, they also found that black and Latino drivers are more likely to be searched for contraband — even though white drivers are consistently more likely to be found with contraband. They also found that legalization of marijuana in Colorado and Washington has caused fewer drivers to be searched during a stop, but that it did not alter the increased frequency with which black and Latino drivers are searched.
  • A 2015 county-level study of police shootings from 2011 to 2014 found “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.” The study also found “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.”
  • A 2014 telephone study of urban men found that “participants who reported more police contact also reported more trauma and anxiety symptoms, associations tied to how many stops they reported, the intrusiveness of the encounters, and their perceptions of police fairness,” and that “overall, the burden of police contact in each of these cities falls predominantly on young Black and Latino males.”
  • A 2018 study of SWAT deployments in Maryland found that such deployments were more heavily concentrated in minority neighborhoods, even after adjusting for crime rates. The study also found that more heavily militarized policing in those areas had little effect on public safety, but did erode public trust in police among residents.
  • A 2018 study of bail practices in New Orleans found that black people are more likely to be required to pay bail, are more likely to have higher bail, are less likely to be able to afford bail and, therefore, are more likely to remain incarcerated before trial.
  • A 2018 study of traffic stops in Vermont found that black drivers are up to four times more likely than white drivers to be searched during a traffic stop, even though white drivers are 30 to 50 percent more likely to be found with contraband.
  • A 2018 survey of bail practices in Miami and Philadelphia found that “bail judges are racially biased against black defendants, with substantially more racial bias among both inexperienced and part-time judges. We find suggestive evidence that this racial bias is driven by bail judges relying on inaccurate stereotypes that exaggerate the relative danger of releasing black defendants.”
  • A 2018 survey found that 63 percent of blacks have had a family member incarcerated, versus 42 percent of whites.
  • While black youths make up 14 percent of the youth population, a 2018 study found that they make up 53 percent of minors transferred to adult court for offenses against persons, despite the fact that white and black youth make up nearly an equal percentage of youth charged with such offenses.
  • A review of homicide cases in Missouri between 1997 and 2001 found that both geography and race are important factors in whether a defendant receives the death penalty. Black defendants in the large urban areas of St. Louis and Kansas City were less likely to get the death penalty, likely because of the higher rate of black jurors in jury pools. This also meant that white defendants accused of killing white people were more likely to be sentenced to death as black defendants accused of killing black people.
  • A 2016 review of traffic stops in Bloomfield, N.J., found that though the city is 60 percent white and non-Hispanic, 78 percent of ticketed motorists were black or Hispanic. The study also found that police disproportionately stopped drivers around the city’s southern border, which it shares with towns and cities with larger minority populations.
  • According to a 2018 study by Pew, 1 in 23 black adults in the United States is on parole or probation, versus 1 in 81 white adults. And while blacks make up 13 percent of the U.S. population, they make up 30 percent of those on probation or parole.
  • According to a 2016 study by the Sentencing Project, mass incarceration combined with felon disenfranchisement laws have led to severe underrepresentation of black Americans in the voting electorate. From the study: “One in 13 African Americans of voting age is disenfranchised, a rate more than four times greater than that of non-African Americans. Over 7.4 percent of the adult African American population is disenfranchised compared to 1.8 percent of the non-African American population . . . In four states — Florida (21 percent), Kentucky (26 percent), Tennessee (21 percent), and Virginia (22 percent) — more than one in five African Americans is disenfranchised.” This means that black candidates may get less support than they otherwise would, candidates of all races may pay less attention to issues values by black voters, and black interests in general may be underrepresented in electoral politics.
  • Though blacks make up just under 12 percent of the population in Texas, according to a database kept by the Texas Justice Initiative, they comprise 29 percent of deaths in police custody since 2005, and 27 percent of civilians shot by police officers. Hispanics were underrepresented in both categories.
  • A 2008 study of parole board decisions found that “black offenders spent a longer time in prison awaiting parole compared with white offenders,” and that “the racial and ethnic differences are remained as an influence on parole decision-making after controlling for legal, various individual demographic and community characteristics."
  • A study of 237,000 traffic stops in Rhode Island in 2016 found that blacks comprised 11 percent of those stopped, significantly higher than their 6.5 percent share of the population at large. The study also found that blacks were more likely to be pulled over during the day, when the race of a driver is more easily ascertained.
  • A study of traffic stops in Connecticut in 2013 and 2014 found that blacks made up 13.5 percent of police stops — again, significantly higher than the black population at large (9.9 percent). This study, too, found that minority drivers were more likely to be pulled over during daylight hours.
  • A 2016 study of traffic violations in several Bay Area counties in California found that black and Latino drivers were significantly more likely to be jailed for an inability to pay petty fines for moving violations. White drivers on average were half as likely to be booked for failure to pay, while black drivers were up to 16 times more likely to be jailed over traffic fines. Another study found that black people make up just 6 percent of the population of San Francisco, but more than 70 percent of those seeking legal aid due to driver’s license suspensions over unpaid traffic fines.
  • A study of about 260,000 traffic stops in San Diego between 2014 and 2015 found that police more likely to search black and Latino drivers than white drivers, even though they were more likely to find contraband on white drivers.
  • Studies of traffic stops in Iowa have found that blacks are disproportionately stopped, disproportionately ticketed, searched, and arrested. They were less likely to be let off with a warning.

Read more:

Radley Balko: There’s overwhelming evidence that the criminal-justice system is racist. Here’s the proof.