Does a new study really show that there’s no racial bias in police shootings?

That’s how the New York Times reported Harvard economist Roland Fryer’s new study, which analyzed data from several police departments across the country to measure racial differences in police use of force. Quoctrung Bui and Amanda Cox reported:

A new study confirms that black men and women are treated differently in the hands of law enforcement. They are more likely to be touched, handcuffed, pushed to the ground or pepper-sprayed by a police officer, even after accounting for how, where and when they encounter the police. But when it comes to the most lethal form of force — police shootings — the study finds no racial bias.

But diving deeper into the study, those conclusions are based on some fairly shaky ground. Specifically, the data the study uses only looks at racial biases after a police officer engages with a suspect. That excludes a key driver of racial biases in policing: that police are more likely to stop black people in the first place, producing far more situations in which someone is likely to be shot. The study also looks at a fairly limited number of police departments, meaning its findings may not apply nationwide.

To understand all of that, let’s break down what the study found and the reasons to be skeptical of the sweeping conclusions some are drawing from the research.

The study claims to find no signs of racial bias in lethal police shootings

The New York Times’s description of the study’s findings is correct: There were racial biases in police’s non-lethal use of force, but no detectable racial biases in shootings.

Specifically, black and Hispanic people experienced 50 percent more incidents of non-lethal force. That disparity was consistent in two different data sets: one from New York City, and one from the Police-Public Contact Survey. According to the researchers, several controls, like the civilian’s age, gender, and behavior, slightly reduced but didn’t fully explain the disparities.

In terms of lethal uses of force, however, the study claimed to find no racial disparity in police shootings, based on two data sets.

First, Fryer’s team found that officers in 10 municipalities across three states were roughly equally likely to shoot either black or white suspects who had not attacked them, and black and white victims of police shootings were about equally likely to be unarmed.

But this only looked at cases in which someone was already shot — leaving out cases in which an officer could have fired but chose not to, potentially because of racial bias. So Fryer’s team then focused on detailed police shooting reports from Houston, which let the team look at reports of not just shootings but all arrests in which lethal force may have been justified. Once again, they found no evidence of racial bias — in cases where lethal force was reportedly warranted, police officers weren’t more likely to shoot just because a suspect was black.

That may seem surprising. But it also comes with enormous caveats.

The study is very limited — and some of its suggestions are refuted by other data

As Fryer put it to the New York Times, the lack of evidence of racial disparities in police shootings is “the most surprising result of my career.” But there are several reasons I’m actually not too surprised now that I’ve read the study and its methodology.

For one, the study is looking at a very limited pool of police departments in terms of shootings: 10 jurisdictions in three states in the first data set, and just Houston in the second data set. The study even acknowledges that there are questions about whether the data is nationally representative.

Worse, the data runs into a big problem with selection bias. For police shootings, the researchers looked at data that police departments gave up willingly. A few, including New York City, didn’t hand over their shooting data to the researchers. It’s possible the police departments that refused did so because their data would confirm racial biases. We just don’t know.

The Houston data — the second data set used for police shootings — is also built on police reports of what police claim are arrests in which lethal force was warranted. But given the video evidence we’ve seen in the past couple of years, there’s good reason to not take police at their word. How many of those reports were written to suggest a black suspect was justifiably shot when he in fact wasn’t, just because the officer may have feared drawing scrutiny?

It’s possible that racial disparities in police shootings are driven by how often police stop black people

Perhaps the biggest problem with the study, however, is that it only looks at potential biases after police have initiated an encounter. So the study found that police aren’t more likely to shoot an unarmed black suspect over a white one once the suspect was stopped — but it didn’t look at whether an unarmed black suspect is more likely to be stopped in the first place.

That’s a big deal: It’s possible that racial disparities in police shootings are driven by how often police stop black people. We know, for instance, that black Americans are disproportionately likely to be pulled over in traffic stops. If police are really equally likely to shoot anyone, regardless of race, in traffic stops, then it would make sense that the people who are pulled over more end up getting shot more often.

Thankfully, we actually have four data sets — from the FBI, the Washington Post, the Guardian, and Fatal Encounters — to see whether black people are truly shot more often without trying to erase the potential racial disparity in stops. These data sets are clear: There are big racial disparities in police’s lethal use of force.

For example, in an analysis for Vox, Dara Lind found racial disparities in the FBI data: Black people accounted for 31 percent of police killing victims in 2012, even though they made up just 13 percent of the US population. The data is incomplete because it's based on voluntary reports from police agencies around the country, but it’s some of the most comprehensive data we have — certainly more comprehensive than Fryer’s study.

It’s unclear why the study didn’t look at these data sets. (Fryer didn’t return an email or phone call asking for comment.) But they show that at some level, there really is a racial disparity. People are not just imagining things.

Despite big limitations, the study provides some possible answers

The limitations don’t mean Fryer’s study lacks any important takeaways. For one, the study does suggest that racial disparities in police shootings may not come at the moment that a police officer decides to fire his or her gun, but rather at the time a police officer is deployed or a cop decides to stop someone. Or perhaps it’s a result of socioeconomic and other systemic disparities that lead to higher crime in minority neighborhoods, which lead to police interacting with these areas much more often. It will take far more research to find which one of these possibilities is right, but Fryer’s data gives a clue.

But the data doesn’t show that police shootings are free of racial disparities. There is plenty of other data out there to thoroughly refute that suggestion.

The study also suggests that non-lethal use of force by police is racially biased. And it leads Fryer to conclude with this powerful statement: