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The Next Phase of Criminal Justice Reform: Considering Reductions in Sentence Length

By Anise Vance

June 29, 2018

This past April, the Massachusetts Legislature passed a landmark criminal justice reform law that was designed, in large part, to help reduce our state’s incarceration levels. Among many other provisions, it includes reducing some mandatory minimum sentences (although it did add one for opioid-related offenses), decriminalizing minor offenses and improving supports for former prisoners transitioning back to society. These reforms should help reduce incarceration rates, but as we think about the next phase of criminal justice reform, there is an additional key strategy that deserves our consideration: reducing time served.


Over the last four decades, the prison population in the United States has risen dramatically. Increased sentence lengths, especially for violent offenses, contribute heavily to this rise. (The Urban Institute’s A Matter of Time: The Causes and Consequences of Rising Time Served in America’s Prisons presents some good detail on these dynamics.) In 1984, for instance, there were fewer than 40,000 people serving life sentences in the United States. By 2016, that number had quadrupled to more than 160,000 people.  

Large prison populations are, of course, a problem for state and federal budgets. They are also an ineffective tool in fighting crime: There is little evidence to suggest that transitioning prisoners back into society, or incarcerating fewer people, leads to higher crime rates. In fact, research indicates that serving more prison time can actually increase the chances of a former prisoner re-offending.

Sentence lengths are also deeply intertwined with issues of race. A recent study found that black males were given sentences 19.1 percent longer than white males with similar criminal histories, age and education. The war on drugs stands out as a particularly powerful example of racialized treatment in the criminal justice system: Black people are far more likely to be arrested for drug use than white people and face longer average prison sentences.


To understand where Massachusetts stands relative to other states in the length of time served by its prisoners, we used data from the Urban Institute and the National Corrections Reporting Program (NCRP) to divide state prison populations into groups based on how long prisoners have served.1 Then, we calculated the imprisonment rate for each separate group. (The NCRP is a voluntary data collection program, so data is only available for the 35 states that participated.)  

In comparison to other states, Massachusetts’ imprisonment rates across most groups is very low. The Commonwealth’s imprisonment rates for various lengths of stay between 0 and 15 years rank among the five lowest in the country, and the rate for people who have spent 15 to 20 years in prison is the 8th lowest. This suggests that, relative to the nation, Massachusetts has done a good job implementing policies and practices that keep people in jail for a minimal period of time. Those policies and practices likely include issuing shorter initial sentences, providing more effective diversionary programs and making parole a more frequent option.


Massachusetts’ imprisonment rates are low across groups, with the notable exception of those serving 20 or more years.

TIME SERVED (years) RANK (out of 35 states) RATE (per 100,000)
 All  33  176
 0 to 2  34  92
 2 to 5  32  38
 5 to 10  32  21
 10 to 15  32  8
 15 to 20  28  7
 20 to 25  25  4
 25-plus  21  7
Source: Urban Institute. National Corrections Reporting Program.

However, Massachusetts is only average, as opposed to low, in imprisonment rates for people who have been in prison for 20 to 25 years and 25 or more years. Out of the 35 states analyzed, Massachusetts ranks 25th in imprisonment rate for people who have served 20 to 25 years in prison and 21st for those who have served 25 or more years.

As we implement the many important changes included in the recent reform law, advocates and policymakers would be wise to give thought to sentence length in the next round of reforms. Conversations on reducing the time people serve in prison are difficult given that those serving the longest sentences have often been convicted of violent crimes. But if we are going to significantly reduce our incarceration levels, examining the impact of how much time people spend in prison, particularly for those serving 20 or more years, is a key part of the conversation.

1 Please note that we made adjustments to the Massachusetts data because, unlike other states, Massachusetts’ local jails can house people serving sentences of 1 to 2.5 years. In most states, local jails can only house people serving sentences up to 1 year.

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