Why prisons continue to grow, even when crime declines

Using data from Minnesota, an Ohio State University sociologist found that the U.S. criminal justice system felt the reverberations from the increase in violent crime and imprisonment that occurred from the 1960s to the early 1990s.

"The issue is that the average offender who appears before a judge for sentencing today has a much more extensive criminal record than they did in the past," said Ryan King, author of the study and professor of sociology at Ohio State.

King found that the average offender in Minnesota in 1981 had one prior felony. That increased to two prior felonies in 1991 and 2.5 prior felonies in 2013.

"It is much harder for judges to not give prison sentences to repeat offenders, so we have more convicted people going to prison."

In fact, the study found that 15 percent of convicted offenders received a prison sentence in 1981, which increased to 20 percent in 1995, and reached nearly 30 percent in 2013.

King said that it is important to try to replicate these results in other states. But he believes the findings would be similar in most states, because judges across the country emphasize prior records when sentencing offenders.

King presented the study Aug. 22 in Seattle at the annual meeting of the American Sociological Association.

The data needed for a study like this is not available for a national sample. So King used 33 years of data that was held by the Minnesota Sentencing Guidelines Commission. This included case-level information on each of the approximately 355,000 felony convictions in the state between 1981 and 2013.

This data included the criminal history of the offender, the severity of the crime, the sentencing outcome and several demographic variables.

King found that in 1981, fewer than 40 percent of sentenced offenders had criminal records, but almost 60 percent did in 2001.

"Criminal activity can decrease, but the criminal record only goes up. Judges are dealing with more repeat offenders now," he said.

It's not that judges are treating repeat offenders more harshly now than in the past. In fact, once he controlled for criminal record over time, King found that judges appeared to be getting more lenient, not harsher.

Minnesota has guidelines for judges to consult when they are deciding on prison sentences for specific crimes and circumstances. Sentences that went below the guidelines increased from 18 percent to 23 percent from 2001 to 2013. Sentences that went above the guidelines decreased by about 2 percent in that same time period.

That suggests the problem isn't the length of prison sentences, but who is who is being sent to prison, King said.

"Judges' hands are tied, to some extent. It is hard to show leniency and maintain legitimacy in the public eye when you're dealing with a repeat offender, and judges are seeing more of them than they have in the past," he said.

If the United States wants to reduce the number of people in our prisons, King said these results suggest we need a new approach.

"Instead of focusing mainly on first-time offenders, we need to come up with new ways of dealing with offenders who have just one prior conviction," he said.

"If we could find ways to keep them out of prison, that would have a large impact."

Regardless of what else is done, the number of people in prison should decline if crime rates stay where they are, he said.

"But it is going to be a slow process. Our prison populations are going to go down much slower than they went up."