Incarceration of white Americans on the rise

The numbers: The African-American incarceration rate has fallen by 20% nationally and 30% in urban areas since 2005. The study looked at the racial makeup of local jails as collected by the Census of Jails, which is released around every five years, compared to each county's own demographics.

Here are some of the possible causes of the trend of lowering black incarceration rates in jails:

• The rewrites of criminal justice laws: Those have taken place at the state and local level across the country, especially in states like Connecticut, Michigan, Texas, Indiana and Delaware. Ram Subramanian, one of the study's authors, told Axios that the timing of the national conversation about incarceration rates seems to correlate with black incarceration rates beginning to decline around 2005.
• The opioid epidemic: The increases in white incarceration rates are most pronounced in rural areas, known for areas stricken by the opioid epidemic. There were four times as many opioid prescriptions in the U.S. in 2010 as there were in 1999, and twice as many people using heroin in 2013 compared to 2000.
• On the flip side, Laurie Garduque who heads up MacArthur Foundation's Safety and Justice Challenge, told Axios that the jurisdictions she's worked with have been treating the opioid crisis more like a public health problem and "don’t see it as an occasion to bring people in the jails."
• Rural vs. urban access: The differing levels of help with and access to the criminal justice system, depending on where people live, could also impact the overall trends. In rural areas, there can be "less resources, distances are much farther, harder to travel, harder to use economies of scale to build up these programs" compared to urban areas, according to Chris Mai, another author of the study.
• Even when it comes to treating opioid addiction, Garduque pointed out that smaller more rural jurisdictions might not have better alternatives to jail for those struggling with substance abuse than larger jurisdictions might have.

The catch: There are few, if any, standards set for how to collect racial data, and as Mai told Axios, "often times people are not self-identifying, so the jails might classify someone who [would self-identify] as Latino as white." This could partially contribute to the rise in white incarceration numbers.

One big "yes, but:" Subramanian and the other authors of the study said they were frustrated that they couldn't pin down the causes more accurately because of the lack of careful or consistent data collection in local jails. They hope that this study inspires better data collection.

"Race and racial disparity are really hard to talk about, and there's been some reservation in approaching that conversation."

• Last week, Florida's state House of Representatives passed a criminal justice reform bill that calls for better data collection on prisons and jails as well as more transparency in presenting that data. This bill is a first of its kind.

Racial disparities: In 2013, African-Americans were 3.6 times more likely to be incarcerated than white people. But that was an improvement from 1990, when they were almost seven times more likely to be incarcerated.

While black incarceration rates are dropping, Mai told Axios she was struck by "how stark the disparities are that remain." She said the study "empowers people to ask even tougher questions about race" and to really "dig into drivers and possible levers" behind the drop in black incarceration rates in order to magnify the trend.