Demonstrators carry a banner across the Brooklyn Bridge while participating in the March for Racial Justice in New York in October. (Bloomberg)

Over the past several years, police misconduct toward racial minorities has been an explosive topic in U.S. and U.K. public discussion. Mobile phone and security videos have made it possible for nationwide audiences to see police misbehavior for themselves. In the United States, nationwide protests erupted after police killings of Michael Brown in Ferguson, Mo., in 2014 — an effort that is continuing in the NFL’s weekly #TakeAKnee protests. In the United Kingdom, similar protests exploded after the police killing of Mark Duggan in London in 2011. Opinion polls show that in both countries, many racial minorities distrust the police.

Can increasing the numbers of minority police officers reduce police racial misconduct? Between 2000 and 2010, the U.K. government assumed that the answer was yes — and worked to significantly increase the share of ethnic minority police officers in every force within the country. To find out whether racially representative policing made a difference, I investigated — and found out the answer is yes, although not precisely for the reasons expected. Here’s what my research found, and what the United States can learn from across the Atlantic.

Misconduct that varies by race can erode force effectiveness

In January 2017, USA Today reported that the Justice Department found Chicago’s police to be “beset by widespread racial bias, poor training, and feckless oversight of officers accused of misconduct.” That probe reinforced data released in 2015 by the Invisible Institute showing that 61 percent of complaints against police were filed by African Americans, almost double their 32 percent share of the city’s population.

Further, according to this data, misconduct complaints against police officers were less likely to be sustained or result in disciplinary action when the complainant was black. Higher levels of misconduct complaints from a particular racial minority group may significantly erode that group’s trust in and cooperation with the police.

Here’s how I studied the U.K.’s experiment

In 1999, the U.K. government launched an ambitious program to increase the ethnic representativeness of forces throughout the country. The goal was ambitious: Each force was to have a share of ethnic minority officers proportional to the populations of the community it served. For some forces, this meant heavily recruiting ethnic minority officers.

Usually, public workforce demographics are pretty stable over time. This experiment gave me a unique opportunity to test whether an increase in ethnic minority representation would indeed result in a decrease in police misconduct.

Did it work? In short, yes. I studied data on 42 police forces in England and Wales from 2000 to 2010 that were increasing the proportion of ethnic minority officers. Doing so, I found, was associated with a significant decrease in the number of substantiated misconduct complaints. Specifically, a 1.5 percent increase in the share of a force’s ethnic minority officers was associated with an 11 percent reduction in the number of upheld complaints per officer. Further, the share of complaints brought by black citizens decreased — but not the share from other minority citizens such as Asians or those with mixed ethnicity.

But merely changing the numbers won’t fix police misconduct

As a 2014 Washington Post article accurately reported, such police misconduct may not be ended just by increasing the number of racial minority officers. Rather, what seems to be needed is an open discussion of how minority citizens are treated — a discussion that can be prompted by expanding the proportion of minority officers.

By discussing how the force treats minority citizens, white officers are more likely to reappraise the force’s ethical climate and take responsibility for improving individual and collective integrity. The results can be officers’ reduced tendency to act on implicit assumptions that minorities are more unlawful than whites. For instance, in the United Kingdom, I found that a 1.58 percent increase in the share of ethnic minority police officers was associated with a 20 to 39 percent decrease in the proportion of ethnic minority citizens among those subjected to stop and searches.

This evidence suggests that increasing the number of racial minority officers reduces police forces’ use of racial profiling. Moreover, such changes occurred primarily within police forces where racial profiling had been intensively used as a policing tactic.

Sounman Hong is Underwood Distinguished Associate Professor at Yonsei University. His research focuses on how to achieve a more efficient, responsive and accountable public administration.