Getting “tough on crime” sounds good in the abstract. Nearly every politician, regardless of political party, says it is necessary. It certainly sounds good to the average voter. But what does that actually entail? Prisons and jails in the United States are miserable places to visit, let alone actually spend time incarcerated in them. No one wants to be there. They are over-crowded, lack privacy, devoid of natural light, and the prisoners must do what they are told, all day, every day. Despite media depiction of jails as relaxing places, politicians would be hard pressed to make incarceration any more miserable.

The usual method politicians use to get tough on crime is to lengthen prison sentences. The problem is, the United States has been getting tough on crime for 40 years now with only longer sentences to show for it. Our sentences are longer than other any other industrialized nation. (Our crime rates have been dropping since the early nineties, but that has been happening throughout the industrialized world, including countries that have very short sentences.)

More importantly, the average law-abiding citizen has no idea how long sentences are now. People I talk to are often very surprised to hear how long someone can be incarcerated for various crimes. If people do not know how long sentences actually are, how do they know they want them lengthened?

A federal judge by the name of James Gwin ran an unusual experiment. He had jurors write down how long they believed someone they had just convicted should be incarcerated. He did this for 22 trials. He gave the jurors a description of the defendant’s past criminal convictions and then had each juror write down, anonymously, what they felt the appropriate sentence was. On average, jurors recommended sentences that were 36% as long as the minimum sentences under the Federal Sentencing Guidelines. In other words, completely average people thought the person they had just convicted deserved to spend about 1/3 the amount of time incarcerated as the defendant would get under the most lenient sentence using the federal sentencing guidelines.

The argument in favor of longer sentences stems from the belief that criminals are making a rational calculation. In order for longer sentences to deter crime, a criminal must make a calculation like this: “I would rob that house if the jail sentence is 12 months, but if the jail sentence is 18 months, then forget about it.” It just does not seem that people make these calculations before committing crimes. Despite decades of experience, there is scant evidence that anyone is actually deterred by longer sentences.

If society really wants to deter crime, it needs to convince every potential criminal that they are almost certainly going to be caught. At that point, the punishment is less important because everyone knows they will be deprived of whatever benefit they would have gained through crime.

Take this thought experiment: imagine that the punishment for speeding was $5. “Great! Now I am always going to speed,” you might think to yourself. However, imagine there are enough police on the road that you are 90% sure you will be pulled over if you speed, even a little, even if it is for a minute only. Suddenly the calculation changes. Not only would every speeder have a 90% chance of losing $5, but they would also have to deal with the hassle of being pulled over and then mailing payment to the courthouse. Deterrence is sometimes less about the punishment and more about the certainty of being caught.