Tagged: traffic stops

Police Stops and Naïve Denominators

by · Aug 11, 2025 12:19 pm

In their 2025 article published in Crime Science, Jerry Ratcliffe and Shelley Hyland critically examine how reported racial disparities in police stop data can be misleading. They argue that much of the misrepresentation stems from the widespread use of an inappropriate baseline, or “denominator,” when calculating stop rates.

Typically, analysts compare the distribution of police stops across different racial groups to the distribution in the total city population. Unfortunately, this method does not account for differences regarding who is actually more or less likely to encounter police stops. In doing so, this approach ignores important factors such as the uneven geographic distribution of crime and variations in police deployment. According to the authors, by relying on this “naïve denominator,” studies risk overstating racial disparities. Ratcliffe and Hyland’s work challenges researchers, policymakers, and the public to reconsider how police stop data should be interpreted to paint a more accurate and nuanced picture of racial bias in law enforcement.

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PA state police data shows no racial profiling in traffic stops: Study

by · May 25, 2023 12:35 pm

The question of racial bias in police traffic stops is a highly debated issue. Some analyses have shown that certain racial or ethnic groups are disproportionately represented in traffic stops, leading many people to allege racial profiling and discrimination. However, it is not accurate or fair to claim that all police traffic stops are inherently racist. Other factors can contribute to racial disparities in police stops, including differences in driving behavior, geographic location, and crime rates in specific areas. As more research is conducted on this topic, it becomes more apparent how much context and other factors can play a role in traffic stop decisions. For example,  research that adequately accounts for the impact of contextual and situational factors has found that racial disparities may not be as pronounced as previously thought, and that they are often explained by other factors unrelated to race.

This was the case in a recent study examining traffic stops in Pennsylvania, which found no evidence of racial profiling. According to the full-length report, the Pennsylvania State Police (PSP) stopped more than 440,000 drivers in 2022, 78.5% of whom white. In comparison, 14.4% were Black, and 8.2% were Hispanic. To conduct the study, the PSP partnered with Dr. Robin Engel and the National Police Foundation to ensure that the evaluation was independent and external to the department. Overall, these data should inspire public confidence in the police. It also suggests that PSP’s approach could serve as a promising model for other agencies.

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Unsound statistical analysis misrepresents racial profiling in California police stop data

by · Jan 30, 2023 1:53 pm

Findings from the California’s Racial & Identity Profiling Advisory (RIPA) Board’s Annual Report released earlier this month have sparked controversy after the results revealed that nonwhites are dispropotionately represented in police stops. The report also claimed that, of those stopped, nonwhites were searched more frequently, arrested more frequently, and more frequently engaged in physical confrontations with police officers. This led many people to conclude that the police are in fact, racist. However, it’s important to note that the practice of policing is far more complicated than what can be captured in datasets. While these data appear straightforward, studying racial bias is complicated.

There are myriad contextual factors at play that affect officer decisionmaking and police-citizen interactions, such that it is nearly impossible to attribute racial disparities solely to any one cause. Unfortunately, contextual factors are often not easily measured, or they might be ignored on the basis that these details are “less important.” But ignoring these key details leaves us with an incomplete understanding of the dynamics influencing these police encounters. So when it comes to the RIPA Board’s report, the findings seem straightforward, but a closer look shows some holes in the methodology that likely undermine the validity of the findings. To this end, the Peace Officers Research Association of California (PORAC) conducted a critical analysis of the report that highlighted numerous problems with the RIPA data and the methodology used in the report. In this post, I will summarize the key issues raised by the PORAC.

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