U.S. Department of Justice
Office of Justice Programs
National Institute of Justice
NATIONAL INSTITUTE OF JUSTICE
FIVE THINGS ABOUT
DETERRENCE
Deter would-be criminals by using scientific evidence about human behavior and perceptions
about the costs, risks and rewards of crime.
1. The certainty of being caught is a vastly more powerful
deterrent than the punishment.
Research shows clearly that the chance of being caught is a vastly more
effective deterrent than even draconian punishment.
2. Sending an individual convicted of a crime to prison
isn’t a very effective way to deter crime.
Prisons are good for punishing criminals and keeping them off the street, but
prison sentences (particularly long sentences) are unlikely to deter future crime.
Prisons actually may have the opposite effect: Inmates learn more effective
crime strategies from each other, and time spent in prison may desensitize
many to the threat of future imprisonment.
See “Understanding the Relationship Between Sentencing and Deterrence” for
additional discussion on prison as an ineffective deterrent.
3. Police deter crime by increasing the perception that
criminals will be caught and punished.
The police deter crime when they do things that strengthen a criminal’s
perception of the certainty of being caught. Strategies that use the police as
“sentinels,” such as hot spots policing, are particularly effective. A criminal’s
behavior is more likely to be influenced by seeing a police officer with handcuffs
and a radio than by a new law increasing penalties.
4. Increasing the severity of punishment does little to deter
crime.
Laws and policies designed to deter crime by focusing mainly on increasing the
severity of punishment are ineffective partly because criminals know little about
the sanctions for specific crimes.
More severe punishments do not “chasten” individuals convicted of crimes, and
prisons may exacerbate recidivism.
See “Understanding the Relationship Between Sentencing and Deterrence” for
additional discussion on the severity of punishment.
5. There is no proof that the death penalty deters criminals.
According to the National Academy of Sciences, “Research on the deterrent
effect of capital punishment is uninformative about whether capital punishment
increases, decreases, or has no effect on homicide rates.”
In his 2013 essay, “Deterrence in the Twenty-First Century,” Daniel S. Nagin
succinctly summarized the current state of theory and empirical knowledge
about deterrence. The information in this publication is drawn from Nagin’s essay
with additional context provided by NIJ and is presented here to help those who
make policies and laws that are based on science.
Source: Daniel S. Nagin, “Deterrence in the Twenty-First Century,” in Crime
and Justice: A Review of Research, vol. 42: Crime and Justice in America:
1975-2025, ed. Michael Tonry, Chicago: University of Chicago Press, 2013.
1
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U.S. Department of Justice.
National Institute of Justice • Strengthen Science • Advance Justice
May 2016 NCJ 247350
Five Things About Deterrence
NIJ’s “Five Things About Deterrence” summarizes a large body of research
related to deterrence of crime into five points. Two of the five things relate to
the impact of sentencing on deterrence — “Sending an individual convicted of
a crime to prison isn’t a very effective way to deter crime” and “Increasing the
severity of punishment does little to deter crime.” Those are simple assertions,
but the issues of punishment and deterrence are far more complex. This
addendum to the original “Five Things” provides additional context and evidence
regarding those two statements.
It is important to note that while the assertion in the original “Five Things”
focused only on the impact of sentencing on deterring the commission of future
crimes, a prison sentence serves two primary purposes: punishment and
incapacitation. Those two purposes combined are a linchpin of United States
sentencing policy, and those who oversee sentencing or are involved in the
development of sentencing policy should always keep that in mind.
“Sending an individual convicted of a crime to prison isn’t a very
effective way to deter crime.”
Prison is an important option for incapacitating and punishing those who
commit crimes, but the data show long prison sentences do little to deter
people from committing future crimes.
Viewing the findings of research on severity effects in their totality, there is
evidence suggesting that short sentences may be a deterrent. However, a
consistent finding is that increases in already lengthy sentences produce at best
a very modest deterrent effect.
A very small fraction of individuals who commit crimes — about 2 to 5 percent
— are responsible for 50 percent or more of crimes.
2
Locking up these
individuals when they are young and early in their criminal careers could be
an effective strategy to preventing crime if we could identify who they are. The
problem is: we can’t. We have tried to identify the young people most likely to
commit crimes in the future, but the science shows we can’t do it effectively.
It is important to recognize that many of these individuals who offend at higher
rates may already be incarcerated because they put themselves at risk of
apprehension so much more frequently than individuals who offend at lower
rates.
“Increasing the severity of punishment does little to deter crime.”
To clarify the relationship between the severity of punishment and the
deterrence of future crimes, you need to understand:
• The lack of any “chastening” effect from prison sentences,
• That prisons may exacerbate recidivism,
• The different impacts of the certainty versus the severity of punishment on
deterrence, and
• That individuals grow out of criminal activity as they age.
More severe punishments do not “chasten” individuals convicted of crimes.
Some policymakers and practitioners believe that increasing the severity of the
prison experience enhances the “chastening” effect, thereby making individuals
convicted of an offense less likely to commit crimes in the future. In fact,
scientists have found no evidence for the chastening effect.
Prisons may exacerbate recidivism.
Research has found evidence that prison can exacerbate, not reduce,
recidivism. Prisons themselves may be schools for learning to commit crimes. In
2009, Nagin, Cullen and Jonson published a review of evidence on the effect of
imprisonment on reoffending.
3
The review included a sizable number of studies,
including data from outside the U.S. The researchers concluded:
“… compared to non-custodial sanctions, incarceration has a null or mildly
criminogenic impact on future criminal involvement. We caution that this
assessment is not sufficiently firm to guide policy, with the exception that
it calls into question wild claims that imprisonment has strong specific
deterrent effects.”
Certainty has a greater impact on deterrence than severity of punishment.
Severity refers to the length of a sentence. Studies show that for most individuals
convicted of a crime, short to moderate prison sentences may be a deterrent but
longer prison terms produce only a limited deterrent effect. In addition, the crime
prevention benefit falls far short of the social and economic costs.
Certainty refers to the likelihood of being caught and punished for the commission
of a crime. Research underscores the more significant role that certainty plays in
deterrence than severity — it is the certainty of being caught that deters a person
from committing crime, not the fear of being punished or the severity of the
punishment. Effective policing that leads to swift and certain (but not necessarily
severe) sanctions is a better deterrent than the threat of incarceration. In addition,
there is no evidence that the deterrent effect increases when the likelihood of
conviction increases. Nor is there any evidence that the deterrent effect increases
when the likelihood of imprisonment increases.
A person’s age is a powerful factor in deterring crime.
Even those individuals who commit crimes at the highest rates begin to change
their criminal behavior as they age. The data show a steep decline at about age
35.
4
A more severe (i.e., lengthy) prison sentence for convicted individuals who are
naturally aging out of crime does achieve the goal of punishment and incapacitation.
But that incapacitation is a costly way to deter future crimes by aging individuals
who already are less likely to commit those crimes by virtue of age.
Deterrence and Incapacitation
There is an important distinction between
deterrence and incapacitation. Individuals behind
bars cannot commit additional crime — this is
incarceration as incapacitation. Before someone
commits a crime, he or she may fear incarceration
and thus refrain from committing future crimes —
this is incarceration as deterrence.
1. “Five Things About Deterrence” is available at https://ncjrs.gov/pdffiles1/nij/247350.pdf.
2. Mulvey, Edward P., Highlights from Pathways to Desistance: A Longitudinal Study
of Serious Adolescent Offenders, Juvenile Justice Fact Sheet, Washington, DC: U.S.
Department of Justice, Office of Juvenile Justice and Delinquency Prevention, March
2011, NCJ 230971. Available at https://www.ncjrs.gov/pdffiles1/ojjdp/230971.pdf.
3. Nagin, Daniel S., Francis T. Cullen and Cheryl Lero Johnson, “Imprisonment and
Reoffending,” Crime and Justice: A Review of Research, vol. 38, ed. Michael Tonry,
Chicago: University of Chicago Press, 2009: 115-200.
4. Sampson, Robert. J., John H. Laub and E.P. Eggleston, “On the Robustness and Validity
of Groups,” Journal of Quantitative Criminology 20 (1) (2004): 37-42.
2
National Institute of Justice • Strengthen Science • Advance Justice
May 2016
