Data Analysis Reveals Disparities in Chicago Police Enforcement

A comprehensive analysis of data obtained from the Chicago Police Department (CPD) has highlighted significant variations in law enforcement practices between officers of different racial and gender backgrounds. This unique, controlled comparison lends support to the notion that increased diversity within police forces could potentially enhance the overall quality of policing.

Challenges in Obtaining Police Data

Historically, acquiring detailed data from police departments has proven exceptionally difficult due to a multitude of factors. As the study’s authors explain, access to this information has been limited for some time.

This research, conducted by B.A. Ba and colleagues, leverages highly detailed CPD records acquired through a three-year request process. The collaborative effort involves researchers from UC Irvine, the University of Pennsylvania, Princeton University, and Columbia University, with the findings published in Science (open access available).

Methodology and Data Scope

The study encompasses millions of shift and patrol records spanning from 2012 to 2015. The research team meticulously sorted and refined this data to facilitate a specific type of analysis: comparing police work that was identical in all aspects except for the demographic characteristics of the officers involved.

The goal was to establish a baseline. If, for example, no substantial differences were observed between Black and white officers operating in the same district on the same day and at the same time, race could be tentatively excluded as a primary influence on their policing approaches.

Key Findings of the Analysis

The analysis revealed substantial differences that, after accounting for all other variables, correlated specifically with the officer’s race. While these findings may be intuitive to some and contentious to others, the study’s objective was to demonstrate, through empirical data, the existence of race-associated disparities requiring further investigation.

Specific findings include:

• Minority officers (Black and Hispanic) were assigned to significantly different patrol areas, a factor that needed to be accounted for in subsequent analyses.
• Black officers utilized force 35% less frequently than white officers, with the majority of this difference observed in interactions with Black civilians.
• Black officers conducted fewer “discretionary stops” based on “suspicious behavior.”
• Hispanic officers exhibited similar, though less pronounced, reductions in these practices.
• Female officers employed force considerably less often than male officers, particularly in encounters with Black civilians.
• A significant portion of the discrepancies in stops, arrests, and force application stemmed from variations in the pursuit of minor offenses, especially in predominantly Black neighborhoods.

Conversely, the data indicated that white male officers tended to stop, arrest, and use force more often, particularly towards people of color, and frequently in connection with minor infractions or vaguely justified “discretionary stops.”

This diagram illustrates a sample of the collected data, depicting stops, arrests, and uses of force by officers within the Wentworth District of Chicago. Image Credits: Science

Interpreting the Results and Causal Mechanisms

The researchers emphasize that while the patterns observed appear compelling, it’s crucial to acknowledge the absence of a studied or proposed causal mechanism. They explicitly state that the data can be interpreted in multiple ways.

One interpretation suggests that Black officers may exercise leniency regarding minor offenses, which has a limited impact on public safety, as violent crimes are addressed similarly regardless of officer race or gender. The alternative – systemic racism – carries far more detrimental consequences. While these interpretations are “observationally equivalent” within the scope of this data, they differ significantly in their potential impact.

Implications and the Need for Further Study

In a commentary accompanying the paper, Phillip Atiba Goff of Yale University highlights the profound implications of these findings, emphasizing the risks of ignoring them.

Essentially, police departments may need to reassess their resource allocation and consider the possibility that a substantial portion of officer activity may yield little, no, or even negative benefits to the community. As Goff concludes, a critical evaluation of current practices is warranted.

The Importance of Data Transparency

This revealing study was made possible by the release of data from the Chicago Police Department, compelled by the authors and legal authorities. Obtaining large-scale data from police departments remains challenging, hindering national-level analysis. The authors acknowledge that their findings, specific to Chicago, may not be universally applicable.

However, this serves as a call to action. If research reveals problems of this magnitude when real data is finally accessible, all police departments should carefully weigh the advantages of transparency and collaboration against the risks of continued data obfuscation.