Stanford, California - In any penal system, controlling the misbehavior of prisoners is challenging and costly. However, reducing the operational costs of prisons is possible when good behavior is rewarded, a Stanford professor says.

It is always socially desirable to reward good behavior with either a reduced sentence or parole, according to Stanford's A. Mitchell Polinsky, an economist and director of the John M. Olin Program in Law and Economics.

In a new study, Polinsky examined three ways of rewarding prisoners: a reduced sentence (commonly referred to as time off), the partial conversion of a sentence to a period of parole, and privileges granted while in jail. Of the three, only parole has been previously studied as a reward system from the perspective of deterrence, he said.

'Something better than parole'

"I've been interested in the economics of criminal law and criminal justice policy for a long time," Polinsky said. "When I started thinking about this question, there were only two other papers that looked at the deterrent effects of parole as an alternative to prison. And I thought, there might be something better than parole."

The United States spends about $80 billion per year on the criminal justice system, and it costs approximately $30,000 to imprison someone for one year, according to Polinsky. Rewarding prisoners for good behavior by time off or parole is beneficial to the state because prisoners behave better and the length of time they serve in prison declines, both of which lower prison costs, he said.

Polinsky noted that in Ohio the cost of taking care of an average prisoner is $62 a day. But at a super-maximum security prison, a prisoner costs  $149 a day. The cost of controlling badly behaved prisoners is more than twice the cost of controlling well-behaved ones. 

Based on his analysis, the law professor argues that while it is always desirable to reward prisoners for good behavior through either reduced sentences or a positive period of parole, providing privileges as a reward system is the least desirable option. In fact, costs are associated with providing those privileges.

"If a privilege is to now have three calls home to family per week, rather than one, this might require more phones or guards, resulting in increased costs. There is also no reduction in the time served in prison, which does not reduce overall prison costs, " Polinsky said.

As part of this study, Polinsky wanted to explore the relationship between rewarding prisoners and crime rates. Economists could argue that rewarding prisoners might encourage more crime because sentences are shorter, Polinsky said. There could be trade-offs, he said. "How much money can we save by lowering prison costs versus how much more crime will we cause to occur?"

For example, Polinsky said, "You might think that if somebody is considering stealing a car, if they are caught, it is a four-year sentence rather than five if they behave well. So maybe more people will steal cars.

"The reason why reducing sentences should not increase crime is because behaving well in prison is difficult." 

'Psychological straitjacket'

There is a cost to behaving well, which Polinsky describes as putting oneself in a "psychological straightjacket." A prisoner must refrain from certain misconduct, such as assaulting guards, refusing to perform work tasks and possessing drugs.

As his study demonstrates, prisoners incur a cost by behaving well that creates additional deterrences to crime. They might be getting a one-year shorter sentence, but suffer the same overall "disutility" or unhappiness, said Polinsky.

He pointed out that recent events have highlighted the national criminal justice issue. During the summer, President Obama became the first sitting president to visit a federal prison. And on his historic first visit to the United States, Pope Francis went to a correctional facility in Philadelphia.

Currently, more than 2.4 million people are incarcerated in the U.S., according to Polinsky. This is up 700 percent from 1970. For most states, spending on corrections falls behind only health care and education. In 2011, California was required by the U.S. Supreme Court to change prison conditions. Overcrowding was ruled unconstitutional according to the Eighth Amendment, which bans cruel and unusual punishment. The number of state prisoners was at an all-time high of 163,000 in 2006.  In November 2014, California Proposition 47 reclassified several nonviolent felonies to misdemeanors.

"In addition to addressing the problem of overcrowding, my analysis shows that there is an overall benefit to society from rewarding prisoners for good behavior. I believe this system could be beneficial in all countries," Polinsky said.