A new study has found that the income gap between black and white men has worsened in recent decades, a finding contrary to the popular belief that it has been steadily narrowing.

In fact, by some measures, the research showed there has been no change in the income gap between African-American and white males over the last 70 years.

The study is authored by University of Chicago economist Kerwin Kofi Charles and Duke University economist Patrick Bayer, and is the first to look at income inequality while incorporating data from men who aren’t working. The method, said Charles, is a more accurate picture of labor market dynamics because it addresses access -- or lack thereof -- to jobs. While some men might not be working by choice, many simply can’t find a job or are kept out of the workforce by jail or their criminal record.

What Charles and Bayer found was surprising.

When looking at the average earnings for black men versus the average earnings for white men, the gap steadily improved from the 1940s until the mid-1980s. Then, the trend reversed. So much so that by 2015, the gap had widened back to 1950s levels.

“If someone was put in a time capsule in the 1950s and you woke him up in 2015,” said Charles, “there would be absolutely no difference [in his earnings gap]. It’s astounding.”

When comparing how the average black male’s earnings would rank among his white counterparts, the results were even more unnerving.

“What we found is the median rank gap hasn’t changed in 70 years,” said Charles. “It floored us.”

Charles attributes at least some of this lack of progress to an educational attainment gap. While ending segregation and the Civil Rights Movement led to better education for blacks as a group, African-Americans are still playing catchup compared with whites as a whole. Meanwhile, the educational requirements for a decent middle-class job keep getting higher.

For instance: In 1940, when factory jobs were an entry into the middle class, fewer than 10 percent of black men had completed high school while 28 percent of white men had. By 2014, rates for both races were near 90 percent, but college completion rates are still starkly different. More than one-third of white men have completed college while just 17 percent of black men have.

“African-Americans are improving their overall attainment,” said Charles. “But they have a headwind that they’re leaning into.”

To explain the divergence in median earnings in the 1980s, the authors also cited mass incarceration and the loss of manufacturing jobs. Both had a disproportionate impact on blacks and almost had the effect of reversing the progress made under racially targeted policies, such as affirmative action and desegregation. Although the War on Drugs' mass incarceration wasn’t a racial policy on its face, the punishments were much harsher for offenses more commonly committed by minorities. For example, the penalties for crack, more commonly used by poor blacks, was stiffer than for cocaine, more commonly used by whites.

So, more blacks were imprisoned than whites, a fact which not only keeps them out of the labor force but makes it more difficult to get a middle-class job after release.

Charles said punitive policies that might disproportionally impact any race should continue to be re-examined. And he recommended that policymakers don’t necessarily need to focus on race down the line. Instead, promoting policies that disproportionally impact low-income people in a positive way would help lessen the gap.

The research had one final surprise, and it was a positive one.

High-earning black men have made great strides in closing the income gap with their white counterparts over the decades. Unlike for middle-class blacks, race-specific policies have made a notable mark among higher earners because they expanded access to top-tier educational opportunities and high-wage professions, according to the study. That progress also means inequality is now more pronounced among African-Americans.

“The combination means there has never been a time when the experience of the black men at the top has diverged so much from that of their brothers below,” said Charles.