The importance of certainty of punishment in deterring crime

Imagine you’re contemplating crime.

Not just in an abstract sense. You’re actually thinking about going out and doing wrong. The kind of wrong that could land you in jail if things go badly. Why don’t you? The number of factors involved in the answer to that question is huge, but two of them were looked at in some detail in a journal article published more than thirty years ago.

The article, written by Charles H. Logan of the University of Connecticut, was called “General Deterrent Effects of Imprisonment” and was published in the Sept. 1972 issue of Social Forces.

He looked at how the chances of going to jail and the length of time spent there were related to the crime rate in the United States, analyzing official statistics from National Prisoner Statistics and Uniform Crime Reports for each state using correlation and regression techniques. Logan measured severity by calculating the average number of months felony prisoners released from state prisons in 1960 had served.

What he found might surprise you. He found that for most crimes, severe imprisonment didn’t seem to be go along with a drop in crime when only those two variables – severity and crime rate – were compared. The only crime that showed a strong association between the two was homicide. The only way he was able to find a negative correlation between severity and crime rate (where one rises, the other drops) was when he took certainty of imprisonment into account.

Logan measured certainty in two ways. For total felonies he took the number of admissions to state prisons from 1959 to 1963 and divided that by the number of crimes known to police from 1958 to 1962. For individual offences he divided admissions to state prisons in 1960 and 1963 by the number of crimes known to police in 1959 and 1962. According to his data, the states with the higher likelihood of going to jail seemed to have lower crime rates.

Now’s probably a good time to point out that he wasn’t saying that a higher likelihood of going to jail causes a lower crime rate. In fact, he took great pains to point out that the opposite could be true.

Here’s why. It could very well be that a lower crime rate means that police and courts aren’t as busy, which could lead to a higher ratio of people ending up in jail. There are also good reasons to think that high severity and low certainty of imprisonment might go hand-in-hand (and vice versa). Logan writes: “When penalties are low, we may expect the legal system … to operate more smoothly, automatically, and relentlessly, so that certainty of imprisonment will be relatively high. Juries may be more willing to convict and defendants may be more willing to plead guilty or to accept a conviction without appeal.”

He goes on to write that as penalties get longer, it’s possible that judicial authorities will become reluctant “to charge that particular offense” and it will become “harder to get a conviction.”

Bottomline? Based on this study – and there have been a ton since – for most crimes, severe punishments are only associated with lower crime rates when the chances of going to jail are high. And the associations are so low that even when this is the case, there have to be other factors making the crime rate as high or as low as it is.

(Note: This post was recovered from the earlier version of Understanding Crime.)