Serving Time: Average Prison Sentence in the U.S. Is Getting Even Longer

The average amount of time inmates spend in prison has increased significantly, according to a recent study by Washington, D.C., think tank, Urban Institute. The study found the average amount of time served behind bars had risen by about 5 years from 2000 to 2014. Researchers also discovered that black men, in particular, were the majority of the population of inmates serving the longest sentences.

The study, released Wednesday, was compiled from inmate data from 44 states, some of which saw the average longest time served starting at 10 years while other states saw the longest sentences starting at 15 years. In 35 of the states analyzed in the study, there was at least one in every 10 inmates who had served at least 10 years in prison.

Although the average longest prison sentence varied from state to state, researchers noticed the trend of time served and length of stay was growing overall. For example, the average longest time served started with 4.6 years for violent offenders in California in 2000, but by 2014 the average longest time served started at 8.2 years for violent offenders. While in Arizona, for instance, the average longest time served was 4.3 years in 2000 but inched up to just 5.7 years by 2014.

"The key interesting finding—maybe not necessarily surprising to folks—is that time served and length of stay is growing and continues to grow, and importantly the people who are serving particularly long sentences, those prison terms are getting longer and longer," Ryan King, a senior fellow at the Urban Institute and one of the study's authors, told Newsweek via phone call on Friday.

What King was shocked to discover, though, was the intensity of racial disparities among people who had been serving the longest amount of time behind bars. In 35 of the 44 states included in the study, black men accounted for majority overall prison population in regards to longest time served. However, lack of race and ethnicity documented by state prisons made it difficult for researchers to determine the overall percentage of people serving the longest sentences based on race.

"We were limited because the state data reporting is poor on race and ethnicity. Some states tend to be pretty good for white and black [documentation], but a lot of states don't count ethnicity at all. So you're not able to look at white, black, Latino ratios," he said, adding that even with the limited data they were still able to distinguish "significant racial disparities in prisons" as well as even starker disparities as prison terms grew longer.

For instance, in Pennsylvania where 49 percent of the prison population is black, 60 percent of the inmates serving the longest prison terms are black, compared to just 40 percent of people from other ethnicities. In Florida, 48 percent of the overall prison population is black, but 55 percent of the people serving the longest sentences are black.

The age factor of people serving the longest prison sentences was also startling.

"We found that nearly two in five people serving the longest prison terms have been incarcerated before the age of 25. So a lot of young adults, a lot of the people serving these long prison terms were incarcerated as young adults and are now in their 40s and 50s and older," King said. "One in five people in prison for at least 10 years was a black man incarcerated before the age of 25. So to me, that is an even deeper dive to the really concentrated way in which mass incarceration and long prison terms have affected people of color and in particular young black men."

King said he hoped the data will lead to change in the U.S.

"This report makes it really clear that we're going to have to deal with the length of stay, long sentences particularly for people who are in prison for committing violent offenses," he said. "So sparking a conversation that leads to change is a big part of the reason why we conducted this research. But on a basic level, we would also like states to do a better job of collecting data by race and ethnicity so we would actually be able to more effectively measure what the impact of these policies are. Some states are okay, some are really poor. And there's really no excuse for not having an accurate and comprehensive collection of data by race and ethnicity in this day and age."