In its first major report, the independent, bipartisan Council on Criminal Justice has found that racial and ethnic disparities in U.S. prisons and jails, as well as in parole and probation populations, declined from 2000 to 2016 — though the gap is far from closed.

The study’s authors credit the dip to an overall decrease in drug crimes during that time frame. For decades, advocates for criminal justice reform have blamed the “war on drugs” for the country’s disproportionate incarceration rates between white people and people of color.

“If the perception is that this is a bad situation getting worse, the reality is that it’s going from worse to bad,” said Adam Gelb, president and chief executive of the Council on Criminal Justice, an organization founded last summer to bring together reform stakeholders from political, academic, activist and legal backgrounds.

“How much progress,” Gelb said, “is something that’s in the eye of the beholder.”

Across all four observed populations, people of color are still incarcerated and supervised at higher rates than white people. Although the offending rate for black people declined by an average of 3 percent per year, the study found that group’s length of time in the system increased.

The study compares white people in the justice system to those who are black or Hispanic and is based on data from the Bureau of Justice Statistics. The ratios presented were adjusted for the racial and ethnic breakdown of the U.S. adult population.

Overall, it found that race and ethnic disparities were lowest among probation populations and highest within prison and parole groups.

Among state prison populations in 2000, black people were incarcerated at a rate 8.3 times higher than white people, and for Hispanic people the rate was 2.6 times higher than white people. Those ratios fell by 2016 to 5.1-to-1 and 1.6-to-1, respectively, according to the study.

Though state imprisonment disparities between white and black inmates fell across all major crime categories, the largest drop was observed for drug offenses. Black people were imprisoned for drug-related crimes 15 times the rate of white people in 2000. That ratio dropped to 5-to-1 by 2016, the study said.

“That’s a gigantic drop,” Gelb said.

In that same time frame, white women were imprisoned at a higher rate for violent, property and drug crimes, while black women were imprisoned less often for drug crimes — a change that caused the racial disparity between incarcerated black and white women at the state level to fall from 6-to-1 to 2-to-1.

That decline was sharper than the decline among men, the study found.

Over the 16 years that were studied, the number of black men in state prison declined by more than 48,000, while the number of white men increased by more than 59,000. Similarly, the number of incarcerated black women fell by more than 12,000, and the number of white women in prison grew by nearly 25,000.

The incarceration rates for white women grew steadily over time, leading the study’s authors to believe that the opioid epidemic that hit communities nationwide in recent years might explain some of the change — but not all of it.

“The prevailing narrative is that attitudes have changed only recently and due to the opioid epidemic, which has been mostly a white problem. But these trends predate that significantly,” Gelb said. “The ultimate question becomes, are these remaining gaps due to biased decision-making or not?”

The study did not break down the data by state, which means it is unclear which U.S. regions have made the most — or least — improvement. The authors note in their conclusion that “the effects of criminal justice case processing vary by race and type of crime, making it difficult to point to a single factor that accounts for race-specific changes in imprisonment.”

For example, sentencing habits and parole decisions from state to state could affect those rates, the study said.

“Additional data and research are essential to understand why precisely these trends are occurring, nationally and within state and local jurisdictions,” wrote the study’s authors.

The report notes that racial disparities within the federal prison population also declined, but by a smaller margin. Among black and white people, the incarceration rate fell from 8.4-to-1 to 7-to-1 between 2001 and 2017, and the ratio between white and Hispanic people decreased from 7.3-to-1 to 4.6-to-1.

The next step, Gelb said, is to use council resources to serve as both a think tank and task force hub to create policy recommendations that will help course-correct the prevailing disparities.

“It is an extremely complex tangle of factors behind the trends, but we thought it was critical to understand what the actual trends are and to start to unpack them in a way that can point to potential policy solutions,” Gelb said.

Membership of the council is by invitation only. The Board of Trustees is co-chaired by Sally Yates, former deputy attorney general at the Justice Department, and Mark Holden, senior vice president at Koch Industries.

“We see this as helping build a more precise road map of what needs to be done to move us toward being a fairer and more equitable society,” Gelb said. “You can’t just admire and bemoan the numbers — you have to understand them at a deeper level so you can target and focus your efforts to tackle them.”

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