MICHEL MARTIN, HOST:

We're going to talk now about an economic trend that is getting some attention, the wage gap between white Americans and black Americans. It's worse today than it's been in almost 40 years. In 1979, black men were paid 22 percent less than white men for doing the same job. And 2015 the disparity between pay rates for black and white men climbed to 31 percent. That's according to a new study from the Economic Policy Institute. That's a research institution that leans left.

The study's most surprising finding, though, might be that the gaps get even wider when workers have more education. To hear more, we invited one of the authors of the study, Valerie Wilson, to the studio to give us some details. We were also joined by Adia Harvey Wingfield. She's a professor of sociology at Washington University in St. Louis. She studies the ways race, gender and class affect the working world. And I started our conversation by asking Valerie Wilson why these gaps have been growing.

VALERIE WILSON: A big part of what we did in this study was to try to pin down all of the factors that would reasonably affect what workers get paid. We controlled for level of education. We looked at years of experience, what region of the country you live in, whether or not you live in an urban area or a rural area. And even after controlling for those factors, there was a sizable difference between what black and white workers were paid. When we look at how this gap has changed over time, most of the change in that gap hasn't been the result of those observable factors - education, experience, etc. Most of it is that part of the gap that remains, quote, unquote, "unexplained" on the part that we identify as discrimination.

MARTIN: One of the things, again, that leapt out to a lot of people looking at this is that many people, including the president, have continued to press, you know, education, education, education. That is the bulwark against discrimination or it's the antidote to discrimination. And one of the, I think, truly disturbing findings is that that is not the case, that even when all things are equal, that they turn out not to be at least in terms of the salaries. What's your take on this?

WILSON: I think there's an important distinction to be made when we talk about the role of education in the labor market. Unquestionably, people with higher education, more years of schooling earn higher wages, so education is effective in terms of economic mobility. Education is not, however, the answer to racial inequality.

MARTIN: Let's hear from professor Adia Harvey Wingfield. First of all, I have to ask you, as a person who works with data, tell me some of the things that jumped out to you.

ADIA HARVEY WINGFIELD: Well, I wasn't surprised by the wage gap in particular because I think that's pretty consistent with what we would expect to find from the research. But in looking at what I know from the sociological literature, I think that that fills in some gaps as to why we see this happening. For example, my colleague Vinny Reseno (ph) at Ohio State University has done a lot of work that documents the ways in which discrimination is present for workers of color, particularly black workers.

He finds that they're often subjected to different rules than their white counterparts are, that they're held to different standards, that rules that may be applied to them are not necessarily applied to other co-workers. My other colleague Lauren Rivera has done an excellent study that focuses on the hiring processes for workers in the lead professional services firms and what she finds are that these social patterns where people tend to want to hire people who are like them matter in terms of who has access to these jobs in the first place.

MARTIN: One of the findings is that black workers are offered lower starting salaries right out of college. Why might that be?

WINGFIELD: Well, I think, again, that some of the issues that come out from sociological research play a role in this that when black Americans, generally speaking, are largely stereotyped to be less intelligent, less capable, less focused, it's not surprising that that might translate into the perceptions that managers have in terms of offering starting salaries, particularly if their perception is that workers who are white workers are seen to be more suitable for the culture of a particular firm or the culture and the unspoken norms of a particular environment. I think that these types of stereotypes and perceptions exist in the broader society and that hiring managers aren't exempt from being influenced by them.

MARTIN: I have to ask the question that there will be those who will listen to this and say if these workers - white workers - are getting paid more, then they must be more qualified.

WILSON: No, that's not the case.

WINGFIELD: No, and her data show that that's not the case and the bulk of sociological research makes the point to show that that's not the case that we aren't looking at a disparity in terms of qualifications or education or experience. When those things are controlled for, then if there's still a disparity, then that disparity can be attributed to discrimination. And the research shows that those discriminatory processes are in place.

MARTIN: Before we let you go - we're running out of time - I wanted to ask if people agree that this is not acceptable that people who are equally qualified should be equally desired and should be equally compensated, and that is not the case, what should they do?

WILSON: So the other sort of big finding from this report is that this widening of the racial wage gap has happened in a time we've seen overall growing wage inequality. So there are really two approaches here. One is to address that broader issue of wage stagnation that we see affecting black and white workers alike, but then on the specific - race-specific side of things, we really have to begin to sort of pull back the covers because a lot of this happens because workers don't know what other people in their job are making. A lot of that has to do with which employers are required to report on what they pay workers by race, ethnicity and gender, as well as the fact that, you know, we've gone through different administrations over time when there's been less emphasis and enforcement of existing anti-discrimination laws. So I think that we have to combine both the broad economic policies that are going to boost wages for all workers - middle-class workers in particular - but then also those very race-specific solutions as well.

MARTIN: Valerie Wilson is the director of the Economic Policy Institute's program on race, ethnicity and the economy, and she's one of the authors of a new report on black-white wage gaps. Adia Harvey Wingfield is a professor of sociology at Washington University in St. Louis. Valerie Wilson was here in Washington. Adia Harvey Wingfield was in St. Louis. Thank you both so much for joining us.

WINGFIELD: Thank you.

WILSON: Thank you. Transcript provided by NPR, Copyright NPR.