Disparities between Black and white state imprisonment rates are continuing to decline, but at a slower rate than in previous years, according to a report recently released by the Council on Criminal Justice.

The report found that from 2000 to 2020, the disparity in Black and white state imprisonment rates fell 40%. Half of the disparity reduction occurred from 2000 to 2005, according to the report.

Thaddeus Johnson, one of the authors of the report and an assistant professor of criminal justice and criminology at Georgia State University's Andrew Young School of Policy Studies, said Thursday during a webinar on the report's findings that the disparity reduction was driven by decreasing Black imprisonment rates.

"The black imprisonment rates fell almost continuously throughout the study period between 2000 and 2020, dropping nearly 50%; comparatively, the white imprisonment rate fell about 10% during the same time span," Johnson said.

The report is the second study that the council has released on racial disparities in imprisonment rates. In 2019, the council released a report examining data from 2000 to 2016 and found that racial disparities in imprisonment rates were declining.

The latest report expands on the 2019 study with newly available federal data on imprisonment rates from 2016 to 2020. The report doesn't draw conclusions about what policy changes, if any, have caused the disparities to fall. 

The council plans to release more reports in the coming months on disparities in the imprisonment rates of female populations, how disparities in imprisonment rates compare between states and policy changes that may have fueled reductions in racial disparities.

The latest report found that disparities in Black and white imprisonment rates dropped for violent, property, drug and public order offenses. The largest decrease in disparity occurred for drug crimes.

"Disparity in drug imprisonment rates fell by 75%; that drop accounted for about half of the overall decrease in the Black-white imprisonment rate disparity," the report said.

In addition to examining racial disparities in imprisonment rates, the report looked at racial disparities in the rates of arrests, prison admissions and prison time served.

The report found that racial disparities in Black and white rates of arrests and prison admissions also decreased.

From 2000 to 2019, the disparity in Black and white prison admissions rates fell 57%, but racial differences in admissions still account for the majority of the disparity in Black and white imprisonment rates, according to the report.

Arrest rates for property and drug offenses decreased for both Black and white adults, but decreased more for Black adults, reducing the racial disparity between Black and white arrest rates for those offenses, the report found.

Property crime arrest rates decreased 47% for Black adults and 18% for white adults from 2000 to 2019, while drug arrest rates dropped 52% for Black adults and 7% for white adults during the same time period, according to the report.

However, the decline in racial disparities in Black and white rates of arrests and prison admissions is being offset by an increased disparity in Black and white length of prison stay, according to the report.

The report found that the average expected length of imprisonment for Black people increased from 2.2 years to 2.5 years from 2000 to 2019, while the average expected length of imprisonment for white people decreased from two years to 1.8 years during the same time period.

"Without significant reductions in rates of violent offending and length of prison terms, or changes in the influence of criminal history on sentencing and release policies, significant racial disparities in imprisonment will persist," the report concluded.

--Editing by Karin Roberts.