Police Facebook Posts Disproportionately Highlight Crimes Involving Black Suspects, Study Finds

Legal scholars from Stanford Law School, Duke University School of Law, and the University of Chicago Law School examined close to 100,000 crime-related posts from 14,000 Facebook pages maintained by U.S. law enforcement agencies between 2010 and 2019. The researchers found that Facebook users are exposed to posts that overrepresent Black suspects by 25 percentage points relative to local arrest rates. The researchers also found that the disproportionate exposure of Black suspects occurred across crime types and geographic regions and that it increased with the proportion of Republican voters and non-Black residents in a jurisdiction. 

Stanford Law School Associate Professor Julian Nyarko, the corresponding author of the study, Duke Law School Professor Ben Grunwald and University of Chicago Law School Professor John Rappaport outlined their findings in a research paper titled “Police Agencies on Facebook Overreport on Black Suspects,” published November 2 in the peer-reviewed journal Proceedings of the National Academy of Sciences (PNAS). The research was funded in part by the Stanford Institute for Human-Centered AI (HAI). 

While recent studies have found a decline in overreporting of crimes involving Black suspects in traditional media outlets, a September 2021 report by Pew Research Center found that approximately 31 percent of Americans say they regularly get news through Facebook. 

“The ascent of social media as a source of crime news requires a ground-up rethinking of this issue,” the authors wrote. “Whereas traditional media can constrain and filter how law enforcement communicates with the public, social media has no external gatekeepers. Instead, law enforcement itself decides when and how to report on crime.”

“A substantial body of research shows that crime news that is disseminated through social media exacerbates the public’s fear of crime more than news in traditional media,” said Nyarko. “This may be due, in part, to the more active nature of reader engagement on these platforms – engagement (such as reposting and sharing) that may amplify racial stereotypes. ”

Nationwide Study Merged Multiple Datasets

Nyarko and his coauthors constructed their dataset using CrowdTangle, a website that tracks interactions on public content from Facebook pages and groups. In addition to the posts themselves, they extracted metadata such as the number and types of user interactions and the number of page followers. Using Google Maps, the researchers then associated posts with the geolocation of their originating agencies. They used several algorithms to identify posts that describe both a crime and the race of a suspect. 

Finally, Nyarko and his coauthors matched agency Facebook pages, and by extension their posts, to agencies in the FBI’s Uniform Crime Reports (UCR), the most commonly used dataset in research about crime. The researchers brought in additional data from the UCR, including annual arrest data by race. From the universe of all 100,000 race-crime posts, they analyzed the nearly 70,000 matched posts about serious, “Part I” UCR offenses, for which arrest data are collected most reliably. The resulting dataset allowed them to compare crime reports on Facebook to actual arrest statistics for each agency.

The PNAS paper authors note that their research did not identify the causes of overexposure of Black suspects by law enforcement, whether driven by racial animus, implicit bias, or other neutral factors. “Our analysis is descriptive in nature and thus is not designed to fully identify the causal mechanisms that led to the racial disparities in exposure,” the researchers wrote. 

But even unwitting overexposure can impose substantial social costs, they noted.

“With an ever-growing share of the public relying on Facebook and other social media platforms for news, including about local crime, our research illuminates how law enforcement agencies may shape the public’s views about who commits crime,” said Nyarko. “We plan to continue this research with other social media channels, including Nextdoor, and hope this data will be used to inform policy.”

This story was first published on Stanford Law School's News and Announcements.