© Reuters/Brendan McDermid
The first-of-a-kind study from the University of Wisconsin compared time served by inmates in public and private prisons in Mississippi, between 1996 and 2004, to determine whether private prisons were more cost effective and whether they were leading to lower crime rates through rehabilitation programs.
The study found that private prison operators were increasing inmates' prison sentences by 60 to 90 additional days (roughly 4 to 7 percent) for the average prisoner through a scheme of prison conduct violations. The additional two to three months were leading to an average additional cost per prisoner of $3,000 and eroding any costs savings the state was trying to achieve.
"If inmates sent to private prisons somehow serve longer terms, this undermines the very cost benefit that makes private prisons attractive relative to public prisons," said Anita Mukherjee, an assistant professor of actuary science at the University of Wisconsin, and the study's author, in a statement.
Mississippi has the highest incarceration rate in the US, with 40 percent of inmates held in private prisons. Since 1980, states have been contracting with private prison operators to help reduce costs and expand bed capacity, which has led to the US contracting 10 percent of its 2.3 million prison population out to private prisons. The private prison contracting industry is now worth $5 billion. Under Mississippi state law, private prisons have to provide cost savings of 10 percent compared to public prisons.
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