Friday, 2 December 2011

Certainty and Severity

We usually expect crime to be more responsive to the certainty of punishment than to its severity in terms of fine or sentence imposed. The best explanation I've seen is that having any criminal record comes with a very large fixed cost regardless of sentence imposed: your chances for professional employment diminish and social sanctions apply. Consequently, differences in delivered sentences have only minor effect on the likelihood of offending if the informal penalty is large relative to the formal penalty and is not particularly increasing in the judicial penalty assessed.

A Canadian Ministry of Justice report finds that differences in first offence drink drive sentencing do not predict an offender's likelihood of re-offending. A straight punishment severity story would have that a more harshly punished offender will be more nervous about reoffending than will someone let off with a light sentence; that wasn't found.

The CTV piece concludes this is due to the severity of sentencing having little effect; they then conclude that Conservative crackdowns on repeat drink-drive offenders will not affect the likelihood of reoffending. But I'd be a bit nervous about drawing that conclusion without seeing the internal report cited. A few things I'd worry about:

  • Suppose a judge assesses costlier penalties on offenders who are more likely to re-offend and lighter ones on those less likely to re-offend. In the absence of any penalties, there would be strong differences in likelihood of re-offending; in an equal-penalty treatment, there would also be reasonably large heterogeneity in recidivism rates. The higher penalties assessed to those perceived to be high risk may bring their recidivism rates down to those exhibited by lower risk offenders. You need some instrument to sort out causality.
  • Drink driving convictions in Canada come with a one-year driving suspension for first time offenders. The costs of this are massive relative to a $600 or $1000 fine. How much would you be willing to pay to avoid a one-year license suspension? $5k? More? We'd need to know a lot more about the monetized value of the variance in imposed first-time penalties to know whether it's washed out by the fixed cost of losing your licence.
  • If the variation in penalties for first offenders is small relative to the increase in penalties assessed for recidivists, it's hard to draw conclusions from the former about the latter.

HT: @DanGardner

1 comment:

  1. Mark Kleiman's "When Brute Force Fails" is an excellent book, in part because of the evidence it gives on how shifting from severity to certainty can deter folks we'd normally think the most undeterrable.