These graphs represent a year-end snapshot of the average number of years that people in state prisons have been incarcerated so far. Many will go on to serve considerably more time.
Each state’s story is unique, but we found a consistent upward trend in the amount of time people spend in state prisons. Since 2000, the average time served has risen in all 44 states (including the District of Columbia) that reported complete data to the National Corrections Reporting Program.
In some states, this rise began years earlier. But these recent trends suggest that most states are still feeling the effects of policy decisions from the 1980s and ’90s that were designed to keep people in prison longer.
In most states, this trend is mostly—if not entirely—driven by an increase in time served for violent crimes. These changes have an outsized effect on the prison population, because people convicted of violent offenses make up more than half the people in state prisons and the majority of people with long prison terms.
Reforms tend to focus on low-level crimes. And though some have helped reduce prison time for minor offenses, the narrow focus of these reforms has intentionally excluded those who stay in prison the longest.
We looked at the 10 percent of the prison population in each state serving the longest terms, a measure that reflects each state’s unique population and policy environment. In most states, the average time served by the top 10 percent rose much more sharply relative to the rest of the prison population.
The average time served by this group, according to the most recent state data available, ranged widely from 9.5 years in South Dakota to 26.1 years in Massachusetts. In most states, the top 10 percent have spent an average of 15–25 years in prison so far.
For many states, this represents a staggering increase. In Michigan, for example, the average time served among the top 10 percent was 10 years in 1989. In 2013, the top 10 percent had served 26 years—a 160 percent increase. California saw its average among this group rise from 9.7 years to 24.9 between 1992 and 2014. In nearly half the states we looked at, the average time served by this group has risen by more than 5 years since 2000.
These steep increases over time and the variation across states points to the power of state-specific policy decisions.
In 35 states, at least 1 in 10 people in prison have been there for a decade or more, according to the most recent data available. In California and Michigan, nearly 1 in 4 people have served at least 10 years.
In some states, this group may be growing mainly because fewer people are serving short terms. This trend is to be expected in states that have cut admissions and/or prison time for low-level offenses. For example, California’s Public Safety Realignment Act of 2011 sentenced thousands of people convicted of lesser offenses to county jails and probation, radically shifting the makeup of its prisons toward people with more serious convictions.
The shifting makeup of state prison populations doesn’t tell the entire story, as the absolute number of people serving 10 years or more has also increased. In at least 11 states, this number has more than doubled since 2000.
Tens of thousands of people nationwide are serving these long sentences, and many will stay much longer.