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The federal prison population in the U.S. is at an all-time high. Meanwhile, the crime rate in the U.S. is at a historic low. But those two variables may not be as directly linked as it appears on the surface.

A California Department of Corrections officer looks on as inmates at Chino State Prison exercise in the yard December 10, 2010 in Chino, California. (National Journal)
National Journal

A new study from the Pew Charitable Trusts looked at the crime rate per 100,000 residents for each state in 1994, and compared that number with the 2012 rates. It also looks at the rate of imprisonment in state and federal prisons across the country.

The report found that between 1994 and 2012, every state but one has seen an overall decrease in crime. That one state would be West Virginia, where the crime rate has gone up 6 percent over that time. What gives?

It's hard to pinpoint which variables lead to less crime in a state, but there is one constant. The seven states that have seen a decrease in their imprisonment rates over the past 20 years have all seen a corresponding drop in crime. To put it more simply, fewer people in prison correlates with less crime overall.

In New York, for example, the imprisonment rate dropped by nearly a quarter. Over the same period of time, the crime rate in New York also dropped — by more than half. In West Virginia — again, the only state that has seen an increase in its crime rate — its imprisonment rate tripled, the largest increase in the nation.

For some tough-on-crime advocates, this idea may seem counterintuitive. Shouldn't imprisoning more criminals lead to fewer criminals on the street, committing crimes? This data suggests that that isn't the case.

Of course, there are many intervening factors that could account for the drop in crime in those states that are not linked to imprisonment rate. It's a chicken-egg situation: Does a decrease in crime lead to fewer people in prison, or vice versa? Or neither?

The only real constant is that crime in America is at historic lows. Over the past 20 years, violent crime in the U.S. has dropped 48.2 percent. It's difficult to point to one reason that has led to the nationwide decrease in crime — more-aggressive policing and social programs are both likely factors.

Solving the problem of crime in America is as difficult as it is ever-present. In theory, if we could just lock up all the bad guys in the country, we would be safe. But, realistically, the solution to American crime will have to be just as thorny as the problem.

Correction: A previous version of this story mislabeled two data points. The story has also been updated to reflect more analysis from Pew.

This article is from the archive of our partner National Journal.

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