Imprisonment and Crime: Can
Both be Reduced?
Daniel S. Nagin
Carnegie Mellon University
National Association of Sentencing
Commissions
August 7, 2012
Prisoners per 100,000 Pop'n
500
Growth in US Incarceration Rate
400
300
200
100
0
1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Year
Some Observations About the Four
Decade Long Increase in Imprisonment
• Undoubtedly reduced crime but size of
reduction is highly uncertain and also
irrelevant to policy changes from the status
quo
• Social and economics cost have been large
• Correction costs have become unsustainable
• Wide spread recognition across the political
spectrum that crime policy needs to be rethought
Imprisonment and Crime: Can Both Be
Reduced?
Steven Durlauf and Daniel Nagin
(Criminology and Public Policy, 2011)
• Yes
• Requires a shift from severity-based to
certainty-based sanction policies
• Shift in resources from corrections to policing
• Focus today will be on severity component of
the conclusion
When Brute Forces Fails: How to Have
Less Crime and Imprisonment
by Mark Kleiman
• Reaches broadly similar conclusion
Potential Crime Prevention Effects of
Imprisonment
• Incapacitation
• Specific Deterrence—Effect of the experience
of imprisonment on reoffending
• General Deterrence—Effect of the threat of
punishment on offending
Why Deterrence Is Important to Crime
Control Policy
• Crime control by incapacitation necessarily
increases imprisonment
• Crime control with deterrence can reduce
both crime and imprisonment—if the crime is
deterred there is no need for punishment
Key Conclusion of Recent Literature
Reviews
• The marginal deterrent effect of increasing already
lengthy prison sentences is modest at best.
• Incapacitation effects seem to decline with the
scale of imprisonment
• The strategic deployment police has a substantial
marginal deterrent effect.
• No evidence of a specific deterrent effect—all
evidence points to either no effect or a crime
increasing effect of the experience of
imprisonment
Research on Sentence Length and
Deterrence
• California’s 3-Strikes law at best has had a
modest deterrent effect
• Increased penalties upon reaching age of
majority have no apparent deterrent effect
• Project Exile (Richmond, VA) no apparent
deterrent effect
• Short but certain periods of incarceration do
affect the behavior of active offenders
Figure 2: Marginal Versus Absolute Deterrent
Effects
Crime
Rate
C0
C1
S1
S2
Sentence Length
Policy Implications for Sentencing
• Lengthy prison sentences are not effective
deterrents
• Incapacitating aged criminals is not cost
effective crime control
– Recidivism of releases 45 or older is 45% less than their
18 to 24 counterparts
– 17% of California’s prison population is 50 or older, up
from 6% in 1998
– Nationally, 20% of prison population is 45 or older,
double 20 years ago
– 10% of prison population is serving life terms (4% LWOP)
Bottom line
• Lengthy sentence can not be justified based
on crime control grounds—they must be
justified on justice grounds
• In an era of tight crime control budgets,
policing (and parole and probation services)
not prisons should receive a larger share of a
smaller pie.
• Need to scale back on sentence length,
particularly of the mandatory minimum and
lengthy variety
Recent Essays
• Imprisonment and Crime: Can Both Be
Reduced?
• Imprisonment and Reoffending
• Deterrence: A Review of the Evidence by a
Criminologist for Economists
• Deterrence in the 21st Century: A Review of
the Evidence
• My email address: dn03@andrew.cmu.edu
Thank you
dn03@andrew.cmu.edu