Estimating the Deterrent Effect of Incarceration Using Sentencing Enhancements

57 Pages Posted: 4 May 2011

See all articles by David Abrams

David Abrams

University of Pennsylvania Carey Law School

Date Written: January 2011


Increasing criminal sanctions may reduce crime through two primary mechanisms: deterrence and incapacitation. Disentangling their effects is crucial, since each mechanism has different implications for optimal policy setting. I use the introduction of state add-on gun laws, which enhance sentences for defendants possessing a firearm during the commission of a felony, to isolate the deterrent effect of incarceration. Defendants subject to add-ons would be incarcerated in the absence of the law change, so any short-term impact on crime can be attributed solely to deterrence. Using cross-state variation in the timing of law passage dates, I find that the average add-on gun law results in a roughly 5 percent decline in gun robberies within the first three years. This result is robust to a number of specification tests and does not appear to be associated with large spillovers to other types of crime.

Keywords: Punishment, mandatory minimum sentencing, incarceration, sentence length, enhancement, armed robbery, use of a gun in the commission of a crime, general deterrence, empirical research, forecasting and simulation, ascertaining disparities in criminal behavior, add-ons, add-on gun laws

JEL Classification: C79, J24, K14, K42

Suggested Citation

Abrams, David S., Estimating the Deterrent Effect of Incarceration Using Sentencing Enhancements (January 2011). U of Penn, Inst for Law & Econ Research Paper No. 11-13, Available at SSRN: or

David S. Abrams (Contact Author)

University of Pennsylvania Carey Law School ( email )

3501 Sansom Street
Philadelphia, PA 19104
United States

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