Posted on October 16, 2015

Police Killings of Blacks: What the Data Says

Sendhil Mullainathan, New York Times, October 16, 2015

Tamir Rice. Eric Garner. Walter Scott. Michael Brown. Each killing raises a disturbing question: Would any of these people have been killed by police officers if they had been white?

{snip}

As an economist who has studied racial discrimination, I’ve begun to look at these appalling deaths from a different angle. There is ample statistical evidence of large and persistent racial bias in other areas–from labor markets to online retail markets. So I expected that police prejudice would be a major factor in accounting for the killings of African-Americans. But when I looked at the numbers, that’s not exactly what I found.

I’m not saying that the police in these specific cases are free of racial bias. I can’t answer that question. But what the data does suggest is that eliminating the biases of all police officers would do little to materially reduce the total number of African-American killings. Police bias may well be a significant problem, but in accounting for why some of these encounters turn into killings, it is swamped by other, bigger problems that plague our society, our economy and our criminal justice system.

To understand how this can be, let us start with the statistics on police killings. According to the F.B.I.’s Supplementary Homicide Report, 31.8 percent of people shot by the police were African-American, a proportion more than two and a half times the 13.2 percent of African-Americans in the general population. While this data may be imperfect, other sources in individual cities or states, such as in California or New York City, show very similar patterns.

The data is unequivocal. Police killings are a race problem: African-Americans are being killed disproportionately and by a wide margin. And police bias may be responsible. But this data does not prove that biased police officers are more likely to shoot blacks in any given encounter.

Instead, there is another possibility: It is simply that–for reasons that may well include police bias–African-Americans have a very large number of encounters with police officers. Every police encounter contains a risk: The officer might be poorly trained, might act with malice or simply make a mistake, and civilians might do something that is perceived as a threat. The omnipresence of guns exaggerates all these risks.

Such risks exist for people of any race–after all, many people killed by police officers were not black. But having more encounters with police officers, even with officers entirely free of racial bias, can create a greater risk of a fatal shooting.

Arrest data let us measure this possibility. For the entire country, 28.9 percent of arrestees were African-American. This number is not very different from the 31.8 percent of police-shooting victims who were African-Americans. If police discrimination were a big factor in the actual killings, we would have expected a larger gap between the arrest rate and the police-killing rate.

{snip}

If the major problem is then that African-Americans have so many more encounters with police, we must ask why. Of course, here too, police prejudice may be playing a role. After all, police officers decide whom to stop or arrest.

But this is too large a problem to pin on individual officers.

First, the police are at least in part guided by suspect descriptions. And the descriptions provided by victims already show a large racial gap: Nearly 30 percent of reported offenders were black. So if the police simply stopped suspects at a rate matching these descriptions, African-Americans would be encountering police at a rate close to both the arrest and the killing rates.

Second, the choice of where to police is mostly not up to individual officers. And police officers tend to be most active in poor neighborhoods, and African-Americans disproportionately live in poverty.

In fact, the deeper you look, the more it appears that the race problem revealed by the statistics reflects a larger problem: the structure of our society, our laws and policies.

{snip}

Individual police officers did not create these economic policies that limited opportunities or create the harsh sentencing policies that turn minor crimes into lifetime sentences.

We should eliminate police prejudice because it is wrong and because it undermines our democracy. It blights–and all too often destroys–lives.

But there are also structural problems underpinning these killings. We are all responsible for those.