Did a “Minneapolis Effect” and Later De-Policing Cause Firearms Crimes to Spike in 2020?

In 2020, major cities across the country suffered dramatic spikes in homicides and shootings. One hypothesis for explaining these spikes is de-policing: the idea that anti-police protests in the wake of George Floyd’s killing in Minneapolis led police across the nation to pull back from some forms of proactive policing. The basic idea is that anti-police protests in the wake of George Floyd’s killing in Minneapolis led police across the nation to pull back from some forms of proactive policing. The possible consequence, according to this hypothesis, was an increase in homicides and gun violence. This thesis, which I have called the “Minneapolis Effect,” continues to warrant research and investigation. It remains a strong candidate for explaining a significant part of the nation’s homicide and shooting spikes in major cities in 2020.

My chapter in a forthcoming book on violent crime argues that more research should be conducted to specifically examine the relationship between de-policing and firearms offenses. As I explain in the chapter, it is well known that, in 2020, many major cities across the country suffered from dramatic spikes in homicides and shootings. According to the National Center for Health Statistics, the homicide rate in the U.S. increased from 6.0 homicides in 2019 to 7.8 per 100,000 in 2020. This was the largest one-year increase in homicide rates ever recorded. Similarly, a major analysis of a sample of 34 cities by Professor Richard Rosenfeld et al. for the Council on Criminal Justice reported that homicides in 2020 were 30% higher than in 2019. The study also found that a structural break occurred in the homicide trends in June of that year, indicating large, statistically significant increases in homicide rates after adjusting for seasonality and long-term trends. Nationally, nearly 5,000 more Americans died that year due to the increase in homicides. And much of the increase in homicides was concentrated in the nation’s major cities, apparently in impoverished areas.

While explaining trends in homicide rates in general is a long-debated topic, explaining why thousands of additional victims were killed in a recent year remains a discrete issue that would seem to be within the ken of modern social science.

Early in 2021, I presented my “Minneapolis Effect” thesis in an article published in Federal Sentencing Reporter. My analysis launched from the structural break identified by the Rosenfeld report, which identified June 2020 as the beginning point (the break point)  in the homicide trendline. I described this phenomenon as the “Minneapolis Effect,” drawing a parallel to the earlier “Ferguson Effect” that was offered to explain certain increases in homicides following the shooting of Michael Brown in 2014.

My analysis relied on what appeared to be almost simultaneous increases in homicides and declines in proactive policing—that is, declines in self-initiated policing tactics designed to reduce crime through preventive strategies, such as street stops or anti-gun patrols. Looking at Rosenfeld’s national data, as well as data from five specific cities—Minneapolis, Chicago, Philadelphia, Milwaukee, and New York—I noted that homicides appeared to have spiked above normal trendlines around the beginning of June 2020. I then observed that, just as homicides were spiking, various forms of policing were declining. In particular, some data indicated that after the anti-police protests surrounding George Floyd’s death, some forms of proactive policing declined. For example, police were redeployed to manage the protests, diverting them from directed anti-gun patrols, vehicle and pedestrian stops, frisks for firearms, and other activities that deter the  carrying of illegal firearms. And even after protests began to wane, police pulled back (for various reasons) from aggressive efforts to combat gun crimes. My thesis was that the consequence of reducing law enforcement activity directed against gun violence was, perhaps unsurprisingly, an increase in gun violence. (In America, the vast majority of homicides are committed with firearms.) I found support for this thesis in the data from the cities mentioned above.

My Minneapolis Effect thesis fits within a larger body of research, which tends to support the idea that proactive policing may be particularly effective in reducing gun crimes. I collected the then-existing research in my 2020 article. In the aftermath of George Floyd’s death and subsequent calls for police reform, scholars have discussed de-policing, where officers reduce proactive law enforcement activity in response to heightened scrutiny, police reforms, or negative public sentiment. Now, the empirical literature on de-policing is growing, with several recent studies investigating whether and how police disengagement contributes to broader changes in crime rates, particularly following high-profile police killings.

You can read the details in my chapter. It reviews recent literature on de-policing that has been published since May 2020. In general, this literature provides evidence that some de-policing has occurred in some cities, particularly reductions in discretionary police activities, such as vehicle and pedestrian stops. These studies then analyze whether those reductions have produced increases in certain crime categories. In particular, this chapter summarizes nine new contributions to the de-policing debate, highlighting areas of emerging consensus as well as areas where further research is needed.

My chapter concludes that the emerging empirical evidence, while not conclusive on causation, generally supports the hypothesis that de-policing increases firearms-related crime. Given the magnitude of the crime spikes that may be attributable to de-policing, further research on this firearms-specific hypothesis should be a high priority.