More Time, Less Crime? Estimating the Incapacitative Effect of Sentence Enhancements

Abstract

Sentence enhancements can reduce crime by causing potential offenders to change their behavior and by removing dangerous offenders from society for longer periods of time. I estimate the incapacitative effect of longer sentences by exploiting a 2001 change in Maryland sentencing guidelines that reduced the sentence of 23, 24 and 25 year old males with delinquent records by a mean of 222 days per delinquent 'point'. I find that during this sentence 'disenhancement', offenders were on average arrested for 2.8 criminal acts and were involved in between 1.4 and 1.6 index crimes per person during the period in which they would have otherwise been incarcerated. While significantly lower than previous estimates of incapacitation, I find that on the margin, the social cost of the crimes averted by incapacitation is slightly higher than the marginal cost to the state of imposing a one year sentence enhancement.