Crime Reduction Research

An interesting analysis takes on the question of how to reduce crime.

It starts by establishing that crime is bad, not just due to direct harm, but due to indirect harms like changing how people behave to avoid it. I won't belabor that point.

It then lays out some key facts:

The distribution of criminal behaviour is highly skewed, with a very small proportion of the population accounting for a significant share of total crime. Incapacitation of this group through imprisonment results in a significant reduction in societal exposure to criminal activity.

(i) A study of the Swedish population born between 1958 and 1980 found that 3.9% of the cohort was convicted of a violent crime. A group of persistent offenders accounting for 1% of the total population accounted for 63.2% of all convictions. These offenders were relatively likely to commit offences early, use drugs, and display personality disorders.

(ii) A paper comparing convictions from a UK longitudinal study and a US dataset of self-reported delinquency found that in both cases, criminal behaviour was well described by a power law.

(iii) Some 70% of custodial sentences in England and Wales are handed out to offenders with at least seven previous convictions or cautions; 50% to those with at least 15.

(iv) Roughly 73% of 2016 US federal offenders had previous convictions. Among this group, the average number of convictions was ~6. Around 39.5% of these offenders had prior violent offences.

Offenders often possess characteristics which require greater support both in prison and in general society, and which may make standard models of rational choice a poor fit for their decision-making processes.

[Multiple studies show that people convicted of crimes have "high discount rates" which is to say that they disproportionately care about the short term and short change the long consequences.] . . . .

(iv) Some 53,109 adults in British prisons were being treated for alcohol or drug abuse issues in 2017-18, out of a total prison population of around 82,000.

(vi) The National Institute on Drug Abuse states that ”85% of the [US] prison population has an active substance use disorder or were incarcerated for a crime involving drugs or drug use”

(vi) The UK does not have up-to-date figures on mental health in prisons, but the Institute of Psychiatry estimated over half of prisoners have common mental disorders - PTSD, anxiety, or depression - while another 15% have specialist mental health needs, and 2% acute and serious problems.

(vii) The APA estimates that “at least half of prisoners have some mental health concerns”, and 10-25% of US prisoners serious mental illnesses such as schizophrenia.

The deterrence effect of jail time appears to be relatively weak, in part due to these commonalities. . . . 

(ii) . . .  the majority of any deterrent effect results from the initial period of punishment.

(iii) . . . when . . . the economic return to non-criminal activity . . . is low value the return to crime may be disproportionately high.

(iv) . . . it is not clear whether classical rational behaviour is a good approximation to the behaviour of individuals suffering from mental illness or substance abuse issues.

(v) These suspicions are born out by David Roodman’s excellent analysis of deterrence, which notes that punishments designed under the presumption that increases in the certainty of punishment better dissuades criminal behaviour than the threat of greater sanction did not produce the desired effects.

(vi) Roodman also notes that US studies on increased severity have shown little in the way of strong deterrence effects.

(vii) The existence of significant procedural delays in trials and sentencing may exacerbate this, pushing the eventual punishment further into the discounting window.

Conversely, the deterrence effect of visible policing is relatively high

(i) A study using variation caused by the terror alert level set by the Department of Homeland Security found that crime levels decrease significantly when police presence is increased.

(ii) An Argentine study using variation in policing following terror attacks found a strong deterrent effect of observable police in the immediate vicinity.

(iii) Evidence from the United Kingdom shows that victim-reported crime drops with higher numbers of police, while police recorded crime may increase - indicating a deterrent effect alongside improved reporting.

(iv) Variation in police spending in sync with electoral cycles shows that increases in police force numbers have a strong effect on violent crime.

(v) A review of the literature on hotspot policing found that focusing police attention on high crime areas caused an appreciable decrease in crime, with some evidence that high visibility patrols were more effective than normal patterns of behaviour.

Local interventions can also reduce crime by altering the physical environment

. . .  

(ii) An analysis of the impact of street lighting on crime in the UK found that targeted interventions tended to reduce crime, and also made residents less fearful, potentially reducing costly behavioural alteration. . . . A broader review backs this conclusion, finding that street lighting significantly reduces crime.

(iv) A 2009 review of the literature on the installation of CCTV cameras found that it resulted in a small but significant decrease in criminal activity, particularly in car parks. . . . A similar review conducted in 2019 replicated these findings, with the additional note that active monitoring resulted in a larger reduction than passive systems. . . . One study suggests that the bulk of the benefit is deterrence of automobile theft.

The incapacitation effect of imprisonment is relatively strong

(i) Almost by definition, an individual in prison is highly unlikely to commit a crime against a member of the general public.

(ii) Set against this, they are also more likely to commit crimes within prison. Greater monitoring of behaviour must be set against the lack of possibility for effective further punishment (longer sentences may not act as sufficient deterrent), and an environment which is likely to be criminogenic (see below).

(iii) The cost of crime within prison is likely to be lower to society than the cost of crime without; it is not committed against random members of the population, results in less defensive expenditure or avoidance behaviour, and is focused on a smaller group of individuals in an environment designed to reduce criminal activity.

(iv) Roodman’s review of incarceration notes that multiple studies find strong evidence that incapacitation works to prevent crime. This should be expected.

Certain currently common forms of sentencing are likely to increase reoffending

(i) Turning again to Roodman’s review, there is a fairly solid bed of evidence that US prisons are criminogenic. This is not sufficient to outweigh the benefits of incapacitating serious offenders, but is cause for reappraisal for marginal offenders.

(ii) Harsher prison conditions are associated with greater recidivism. This is unsurprising, as brutalising conditions are unlikely to provide effective conditions for self-improvement. . . . A study of Italian jails shows that worse prison conditions does not reduce future criminal activity, instead driving increases in future criminal behaviour. . . . A study of US jails produced a similar conclusion, with a suggestion that harsher conditions increased crime post-release. . . .

(v) A UK Ministry of Justice report concluded that short-duration sentences if anything increased reoffending relative to court orders.

(vi) Norwegian prisons consistently display low rates of recidivism, and are marked by their civilised treatment of prisoners.

The analysis has conclusions, but I'll draw them myself from this data.

1. Identify the individuals at highest risk of committing serious or repeat crimes and support them so they they don't. This is a fairly modest share of the total population: mostly males who are high school dropouts, have substance abuse problems, have criminal records or juvenile justice records, have particular mental health disorders that put them at high risk, and have with poor non-criminal economic prospects. Substance abuse is generally higher risk than mental health disorders generally (although psychopathy manifests young and is a very high risk factor). 

Gang membership, while hard to establish legally in a civil liberties respecting manner, is also an extremely high risk factor. As of 2017:

According to the DOC, there are now more than 8,000 gang-affiliated inmates and parolees in Colorado divided between at least 135 gangs. That means that roughly one out of every four people in the state prison system is labeled as being in a gang. And there are now more gang members in prison than there are total DOC employees.

Incidentally, killing or incarcerating gang kingpins is absolutely the worst thing you can do if organized crime is a serious problem. (See also here).

As I've previously noted at this blog: "Just as crime gravitates to certain neighborhoods, it also clusters in families: According to one criminologist’s analysis of the National Longitudinal Study of Adolescent Health, 5 percent of families account for more than 50 percent of all arrests."

Less than a quarter of Colorado prison inmates graduated from high school in the ordinary course (as opposed to getting a GED) (compared to about 85%+ of the general population), and just 1% have earned any college degree (compared to about 43% of the general population). Substance abuse is a problem for 79% of inmates. Just 6% of Colorado inmates both have a high school diploma (as opposed to a GED) and don't have a moderate to severe substance abuse problem, and some of the inmates in that 6% have moderate to severe mental health problems.

"As of 2010, 3 percent of the total US population and 15 percent of the African-American male population have served time in prison. People with felony convictions more broadly account for 8 percent of the overall population and 33 percent of the African-American male population." (From Science Daily. The paper is: Sarah K. S. Shannon, Christopher Uggen, Jason Schnittker, Melissa Thompson, Sara Wakefield, Michael Massoglia. "The Growth, Scope, and Spatial Distribution of People With Felony Records in the United States, 1948–2010." Demography (2017). DOI: 10.1007/s13524-017-0611-1).

Traumatic brain injury (TBI) is extremely common in the most difficult inmates. 96% of inmates in a high risk unit of the Denver jail have a history of traumatic brain injury. By comparison, 67%-80% of all jail and prison inmates, nationally, have a history of traumatic brain injury, and 6%-8.5% of the general population has suffered from a traumatic brain injury. In the Denver high risk jail unit, 100% had a prior criminal history, more than 90% had a history of mental illness and more than 90% had a history of substance abuse. More than 77% of the inmates in the high risk unit had all four risk factors. A study reviewing TBI incidence in Australian prisons from 2006 found an 82% TBI incidence rate. Another county jail study from 2003 found an 87% lifetime incidence of TBI. A 1995 study examined the way the substance abuse can exacerbate TBI issues.

2. Incarcerate offenders with high recidivism risk until they no longer have a high recidivism risk. A small percentage of people are convicted of crimes and a small percentage of people who are convicted of crimes commit most of those crimes. Detain the worst and try to avoid criminalizing low risk offenders further with the criminalizing effects of poorly managed prisons.

3. Take the effort to make prison conditions less brutal both to reduce recidivism and to reduce crime within prisons.

4. Longer sentences don't discourage people not currently in prison from committing crimes, and even certainty in sentencing doesn't do that, because criminals don't care about the long run and aren't rational actors.

5. Visible police presence in crime hotspots can work.

6. Good street lighting reduces crime.

7. Actively monitored CCTV in parking lots reduces car theft.

The analysis fails to note, but it is nonetheless true, that strict gun control over large geographic areas is very effective at reducing homicide, suicide, and accidental deaths from firearms.

For example, “shall-issue concealed carry permitting laws were significantly associated with 6.5% higher total homicide rates, 8.6% higher firearm-related homicide rates, and 10.6% higher handgun-specific homicide rates compared with may-issue states.”

The analysis emphasizes the fact that violent crime causes more harm than non-violent crime. But, it misses some key points about prevention of crime, especially, but not only, non-violent crime:

1. Requiring a personal identification number (PIN) to use a credit card greatly reduces credit card fraud. See, e.g., this 2012 study (e.g. U.K. credit card fraud fell 63% when this was done).

2. Tracking technology is now cheap and used well, it can greatly reduce car and bicycle and laptop and phone theft, not just through deterrence and by recovering stolen items, but by catching thieves before they can reoffend.

3. Monitoring markets for stolen goods (including electronic markets) effectively is a good way to catch thieves and to make theft less cost effective.

4. Using forensic technology usually reserved for murders and serious assaults and rapes in burglary cases can greatly reduce burglaries because most burglaries are committed by repeat offenders so if you catch on burglar you prevent many offenses and recover a lot of stolen property.

5. Require small telecoms to adopt anti-spoofing calls used to make fraud calls.

6. Randomly including trackers in a modest percentage of delivered packages in problem areas, and using this information together with security camera data to catch porch pirates can reduce larceny.

7. More effectively blacklisting fraudsters can reduce fraud.

8. We could establish an agency that can identify patterns and networks of fraud activity in social media, and take effective action based upon it.

9. We should legalize one party consent to recording telephone communications to make it easier to catch offenders.

10. Legalizing vice (i.e. drugs, prostitution, and gambling) can greatly reduce crime by making organized crime that maintains black markets unprofitable, and by building trust between police enforcing crimes that have victims and citizens. For example, legalizing prostitution materially reduces sexual assault and drug crime rates.

Legalizing vice (e.g. federally legalizing marijuana) also reduces the amount of cash circulating which can drive robbery, burglary and theft.

11. Allowing adult entertainment businesses in a neighborhood reduces the incidence of rapes in that neighborhood.

11. After a fairly modest number of years after release from prison (about five) without committing a new offense, the risk of committing a new offense approaches barely below background levels.

12. Ignoring juvenile records deprives sentencing authorities of key information because the earlier and more severe your juvenile offenses are, the most likely you are to commit serious future offenses. Juvenile delinquency records are a major risk factor for adult crime. The notion that young offenses are most prone to rehabilitation is mostly false. People do age out of being high crime risks, but only in middle age.

13. The risk of substance abuse, and of schizophrenia and bipolar disorders, is highly hereditary.

14. The risk of poor academic performance leading to behavioral problems in school are highly predictable from early childhood, as is a capacity to defer gratification which is a major risk factor for crime.

15. A large share of crimes are economically motivated, or are violent crimes that are incident to economically motivated crimes. Even quite modest non-criminal economic opportunities for people with criminal records and people at high risk for committing crimes can significantly disfavor crime.

16. Abating lead pollution prevented a lot of crime and should continue. More generally, a 2017 California study of the link between air pollution exposure and delinquency shows a statistically significant link between pollution exposure and delinquency. A related study shows the impacts on air pollution exposure on cognitive development.

Finally, a footnote on race, public safety, and crime:

rates of homicides, gun killings and illicit-drug fatalities [ed. combined] are highest in counties where nine in 10 residents are white and where President Trump won in the 2016 election.

Such counties are not limited to one geographical region. They include Boone County, W.V.; Washington County, Utah; Baxter County, Ark.; and Brown County, Ohio.

Correspondingly, the white Americans who are safest from such deaths are those who live in racially diverse areas such as Los Angeles, New York and Chicago, where two-thirds of residents are nonwhite, where millions of immigrants live, and where voters favored Hillary Clinton in 2016. Nonwhites also are safer in these areas overall, though rates vary by location.  

White Americans are nearly eight times more likely to die from illicit-drug overdoses than murder, the CDC statistics show, a proportion that undoubtedly reflects the heroin and opiate epidemic. But according to FBI data for 2015, when whites are murdered anywhere in the country, the murderer is five times more likely to be white than nonwhite. (This ratio counts only murder cases in which information about the offender is known by law enforcement.)

Overall, white Americans who live in predominantly white and Trump-voting counties are 50% more likely to die from murder, gun violence and drug overdoses [ed. combined] than whites who live in the most diverse and Democratic-voting counties. The more white and Republican a county is, the greater the risk for white Americans.

and a footnote on immigration:

immigration is consistently linked to decreases in violent (e.g., murder) and property (e.g., burglary) crime 

Robert Adelman, et al., "Urban crime rates and the changing face of immigration: Evidence across four decades" 15(1) Journal of Ethnicity in Criminal Justice (November 21, 2016).

Deporting immigrants who are arrested for crimes, surprisingly, has no discernible impact on the crime rate.

And, a footnote on religion and homicide and suicide:

The current study assessed the relationship between national religious affiliation and lethal violence by simultaneously examining homicide and suicide rates. The information on homicide and suicide rates for 124 countries came from the World Health Organization (WHO). Regression results suggested no significant difference in lethal violence between predominantly Catholic and Protestant countries, although Islamic countries revealed significantly lower homicide, suicide, and overall lethal violence rates than non-Islamic countries. Countries with a high level of religious heterogeneity are subject to an increased suicide rate.

Don Soo Chon, "National Religious Affiliation and Integrated Model of Homicide and Suicide" (2016).