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New Tool Maps Racial Disparity in Arrests Across the Country

IPR sociologist Beth Redbird measured racial disparities in data from 1999–2015

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As communities across America have gathered in recent months to protest police abuses, researchers are taking a close look at how, where, and why racial disparities in policing occur. IPR sociologist Beth Redbird is one of them, and with graduate research assistant Kat Albrecht she’s compiled the data for a powerful new visual tool that shows how those disparities have grown over time.

With their new police bias map, Redbird and Albrecht show county by county the extent to which Black Americans are arrested at a higher rate than White Americans — a trend that has only accelerated in recent decades. They also include data on the arrests of Asian Americans and American Indians, the latter of whom saw an increase in disparity that matches that among Blacks.

The tool draws from a recent working paper in which Redbird analyzed data from more than 13,000 law enforcement agencies nationwide. She and Albrecht discovered that even while crime rates fell in recent decades, the racial disparity in arrest rates nearly doubled. As Redbird and Albrecht write, such vast disparities can “delegitimize law enforcement, increase tension between police and citizens, and even increase crime.”

While in 1999, the average law enforcement agency arrested 5.48 Black Americans to 1 White American, that number rose to 9.25 by 2015. Over the same period of time, the average American Indian went from being policed by an agency that arrested 3.7 Natives to 1 White to one that arrested 6.2 Natives. Drawing on data from federal law enforcement, Redbird and Albrecht have assigned each county an “arrest risk ratio,” a measure of racial difference in arrests, adjusted for population demographics.

With the police bias map, users can look at the arrest risk ratio by year, age, and ethnicity. The data come from the Federal Bureau of Investigation's Uniform Crime Reporting (UCR) Program, which consists of monthly arrest data for state and local law enforcement agencies that volunteer it. On average, only around 77% of agencies report in any given year, which results in some gaps in the data.

Crucially, the researchers discovered that the main driver of the increase in disparity is a rise in local agencies arresting juvenile offenders. By 2015, the average police agency arrested 5.5 Black juveniles to 1 White juvenile. The researchers note that police contact has been shown to make young boys who reported no prior criminal behavior more likely to offend in the future, further driving the proven harmful effects of racial disparities in policing.

Data for the map visualization is available online. Read the working paper here.

Beth Redbird is assistant professor of sociology, an IPR fellow, and a CNAIR fellow. Kat Albrecht is an IPR graduate research assistant. The visualization was developed by Northwestern IT Research Computing Services. Austin Alleman and Dan Turner were the lead developers, with input from Christina Maimone and Colby Witherup Wood. Photo from PxHere.

Published: August 14, 2020.