The National Law Journal reported, that the U.S. Supreme Court by a 6-3 vote endorsed a long-standing Bureau of Prisons method of calculating good time credit based on the length of time actually served, not the length of the term imposed by the sentencing judge.
As Justice Stephen Breyer described it in his majority opinion in the case, Barber v. Thomas, No. 09-5201, the formula preferred by the Court would result in 470 days of credit for a well-behaved prisoner serving a 10-year sentence, while the method urged by defendants would result in 540 days of credit.
Justice Anthony M. Kennedy dissented suggesting that the formula adopted by the majority will collectively add ten of thousands of years to federal sentences and cost taxpayers countless millions of dollars.
The issue was raised by a group of Oregon prisoners who challenged the way that "good time" was calculated by the Bureau of Prisons.
To read more: http://www.law.com/jsp/article.jsp?id=1202461112769&Justices_Approve_Bureau_of_Prisons_Calculations_for_Good_Time_Credit