The economic theory of crime predicts that people will break the law only if the expected benefits of doing so exceed the expected costs. Crime can be prevented by raising the likelihood that perpetrators will be apprehended, or by increasing the penalties imposed on convicted criminals.
Everyday experience confirms the theory. Drivers are more careful when photo radars are in operation. Tax evasion is lower in occupations where the professional costs of being charged with tax fraud are high.
So what's wrong with getting tough on crime?
In the real world, people don't behave exactly as predicted by the simple crime theory. Increasing penalties can be counter-productive, as is shown in a fascinating study by Shawn Bushway and Emily Owens. They examine a legal change in the state of Maryland in 2001, which changed the recommended punishments for certain offenses, but not the actual punishments. So, for example, before the change, a convicted criminal might be told, "the recommended punishment for this offense is two years, I'm giving you two." After the change, the same criminal would be told, "the recommended punishment for this offense is five years, I'm giving you two."
Yet a criminal who receives the maximum possible sentence has "had the book thrown at her" - she will perceive that she has received a relatively harsh punishment. A criminal who receives only a fraction of the maximum possible sentence will think that he has gotten off relatively lightly - and be more likely to re-offend. Bushway and Owens found that, "individuals whose punishments were low relative to potential punishment were five percentage points more likely to be rearrested, and were rearrested 17 per cent sooner" than people with the same actual punishment but a higher potential punishment.
Bushway and Owens use their research to critique truth in sentencing laws -- laws that require individuals to serve out their full, or close to their full, sentences. There are two ways to make sure that prisoners serve out their full time. The expensive way is to keep prisoners in jail longer. The cheap way is to reduce sentences. But if tighter parole requirements cause judges to impose shorter sentences, then more people will walk out of court feeling that they have gotten off lightly. They will, therefore, be more likely to re-offend.
Is the solution to establish minimum sentences and impose strict sentencing guidelines? Perhaps this can prevent tighter parole requirements leading to shorter sentences? It's not obvious. A hockey referee who feels that the punishment is too severe just won't make the call. The same is true for judges.
Moreover, it costs thousands of dollars to incarcerate offenders. Imposing longer sentences is an expensive way to deter crime. Sure, putting young offenders in prison gets them off the street. So does Grand Theft Auto and Scream 4. As I argue over on Worthwhile Canadian Initiative, economic research is now showing that movies and video games are a cost-effective way of reducing crime. Why lock potential offenders up at the taxpayer's expense when you can give them Halo and they'll lock themselves away?
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