Since 1994, New York has seen the biggest drop in crime of any state. It also saw the biggest drop in its prison population.
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 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 incarceration in federal prisons by state.
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 prison populations 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.
Of course, there are many intervening factors that could account for the drop in crime in those states that are not linked to prison population. 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.
This post originally appeared on National Journal, an Atlantic partner site.
More from National Journal: