Effect of police in high crime communities

"Model policing tactics are marked by trust, transparency, and collaborations between police and community stakeholders"

American Police
On a per-capita basis we employ 35% fewer police than the world average.



"Growth in the total police force, however, has slowed in recent years after increasing by over 20 percent between 1980 and 1995. After factoring in population growth, total growth in policing rates, the proportion of police to residents, has been flat over the last three and a half decades. Given these patterns, it is unlikely that changes in police staffing levels are a primary driver of the incarceration boom" p. 13- CEA 2016



Over policing in high crime areas
While petty crimes are over policed, high crime neighborhoods are consistently said to be under policed for violent crime

Effect of police investments in crime
"Economic research has consistently shown that police reduce crime in communities, and most estimates show that investments in police reduce crime more effectively than either increasing incarceration or sentence severity" p. 13- CEA 2016. A cost-benefit analysis by Klick and Tabarrok 2010 would justify doubling the number of police on the street


 * According to an analysis by the Brennan center, sending additional police to areas with increasing crime tends to lower crime by around 5-15 percent
 * Estimates from Kilck and Tabarrok 2005 conclude that increasing the number of police on the street, for example, would increase capture rates and deter crime and by doing so it would also reduce the prison population. Tabarrok concludes that a 10% increase in policing would reduce crime by 3 to 5 percent.
 * The Council of Economic Advisers during Obama White House report that " 10 percent increase in police force size decreases crime by 3 to 10 percent."
 * "Several rigorous studies have addressed the problem of the joint determination of police and crime by measuring the crime-reducing impact of police hiring changes caused by external factors unrelated to local crime levels (e.g. Klick and Tabarrok 2005; Evans and Owens 2007; DeAngelo and Hansen 2014). This research shows that police reduce crime on average, and estimates of the impact of a 10 percent increase in police hiring lead to a crime decrease of approximately 3 to 10 percent, depending on the study and type of crime"
 * Owens (2011) finds that larger police forces do not reduce crime through simply arresting more people and increasing incapacitation, instead, investments in police are likely to make communities safer through deterring crime.
 * Stephen Mello of Princeton University assessed the Obama-era increase in federal police funding. Thanks to the stimulus bill, funding for Clinton’s Community Oriented Policing Services (COPS) hiring grant program surged from about $20 million a year in the late-Bush era to $1 billion in 2009. The program design allowed Mello to assess some quasi-random variation in which cities got grants. The data shows that compared to cities that missed out, those that made the cut ended up with police staffing levels that were 3.2 percent higher and crime levels that were 3.5 percent lower.
 * A larger historical survey by Aaron Chalfin and Justin McCrary looked at a large set of police and crime data for midsize to large cities from 1960 to 2010 and concluded that every $1 spent on extra policing generates about $1.63 in social benefits, primarily through fewer murders.

Hot Spotting
There is also some evidence on the efficacy of various policing practices. For example, “hot-spots” policing, a strategy that intensifies policing in high crime locations within a city, may have the capacity to reduce crime with minimal displacement of crime to new areas (Braga, Papachristos and Hureau 2014). CEA 2016

Broken Window Policing
In contrast, research on “broken windows” policing, a strategy that focuses on high levels of enforcement for low-level crimes, has found generally weak crime-reducing effects (Harcourt and Ludwig 2007; Caetano and Maheshri 2013). CEA 2016

Effect of under policing
Devi and Fryer 2020 show that when police were investigated following incidents of deadly force that had gone viral, police activity declined and violent crime spiked. "The leading theory for why some investigations have led to an increase in crimes is a striking decrease in the quantity of police activity"