The commission's analysis of demographic prison data from 2012 to 2016 found that black men serve sentences that are on average 19.1 percent longer than those for white men for similar crimes.
The racial disparity in sentencing can't be accounted for by whether an offender has a history of violence, according to the study by the commission, an independent bipartisan agency that is part of the U.S. federal judiciary branch.
"Violence in an offender’s criminal history does not appear to contribute to the sentence imposed" except as it may factor into a score under sentencing guidelines, the study said.
When accounting for violence in an offender's past, black men received sentences that were on average 20.4 percent longer than that of white men, according to the commission's analysis of fiscal year 2016 data, the only year for which such data is available.
The new study updates an earlier commission report in 2012, known as the Booker report, that came after a Supreme Court decision in 2005, United States vs. Booker, which permitted judges to enhance an offender’s sentence based on “facts” determined by their own judgment. Before then, federal judges were only allowed to sentence an offender based on guidelines provided by the sentencing commission
According to the non-profit organization, The Sentencing Project, the U.S. is the world's leader in incarceration, with 2.2 million people in prison as of 2015, a 500 percent increase over the last 40 years.
The Sentencing Project also found that black men are nearly six times as likely as white men to be incarcerated, and Hispanic men are 2.3 times as likely. For black men in their 30s, one in every 10 is in prison or jail on any given day, according to 2015 data cited by the organization.