SARAH MCCAMMON, HOST:

The FBI recently released their annual statistics on hate crimes across the country. But researchers say the data is flawed, and that could undermine efforts to tackle hate crimes. NPR's Sergio Olmos has been digging into these stats, and he joins us now. Hi, Sergio.

SERGIO OLMOS, BYLINE: Hey, Sarah.

MCCAMMON: So what does this latest FBI report say about hate crimes in America, first of all?

OLMOS: The FBI hate crime statistics reported that last year, there were 7,262 hate crimes across the country. That's a slight decrease from the year before, but researchers say that those numbers may paint an incomplete picture. Law enforcement agencies volunteer to participate. They're not required to send in their data to the FBI. There's 18,000 agencies across the country, and last year, only about two-thirds of those agencies sent in any data. And you might imagine that some of those agencies are small police departments or sheriffs in rural towns, you know, stubbornly refusing to send in their stats, except that that's not the case. The largest cities in America - New York, LA, Chicago - didn't contribute any data.

MCCAMMON: And is this the only way that the government tracks hate crimes?

OLMOS: There's other ways. That's the interesting part. I talked to Eaven Holder at the University of Florida, who published a study looking at 18 years of the FBI's hate crime statistics. He compared it to a different set of data collected by the Bureau of Justice Statistics, widely seen as a more reliable indicator of hate crime stats. So instead of a police officer taking a report, it's researchers asking people directly about their experience to crime. And people tend to open up more. Here's how Eaven Holder described it.

EAVEN HOLDER: So what that database tells us is that, you know, there's 200- to 300,000 hate crime incidents in a given year. And the UCR FBI data records less than 10,000.

OLMOS: And Holder says that even if you look at that data, last year, 80% of the 15,000 agencies that participated reported zero hate crime incidents.

MCCAMMON: Zero hate crimes - I mean, is that reliable? Is that even possible?

OLMOS: There's a mix of reasons why that happened. Some victims may not see themselves as a victim of a hate crime, and some police departments may record, for example, an assault without labeling it a hate crime. And that may be because it's a higher burden of proof to prove the motivation behind a crime. I talked to Jacob Kaplan, who's a professional specialist at the Princeton School of Public and International Affairs. Let's listen to how he described it.

JACOB KAPLAN: There needs to be evidence of bias that plays at least a small part in the crime. And then the police need to have actual evidence, not just, like, I think I was the victim of a hate crime. They need some kind of evidence to suggest that bias was a motivating factor.

OLMOS: So even among police departments that are making a sincere effort to track hate crimes in their district, it's still a challenge.

MCCAMMON: So, Sergio, what could this incomplete data you're describing mean in terms of trying to police hate crimes in the future?

OLMOS: So police and community relationships are already stressed. And researchers say that not taking identity-based crime seriously contributes to a vicious circle where victims of hate may be less likely to turn to the police to solve their problems. And police record less of those and so on, undermining the overall legitimacy of police as an institution, especially in marginalized communities. The Justice Department themselves acknowledge how difficult it is to draw any conclusions from this data set because of the inconsistent way cities are reporting hate crimes year by year. And even if all cities that participated reported their data, among law enforcement, there's just not a universal agreement on what constitutes a hate crime. For example, a mass shooting last year in Atlanta at spa and massage parlors that left eight people dead, including six people who were Asian, were not counted as a hate crime in these stats. So these flawed numbers could mask a very real problem at a time of rising domestic extremism.

MCCAMMON: NPR's Sergio Olmos, thanks so much.

OLMOS: Thank you. Transcript provided by NPR, Copyright NPR.