When I first met Malaki Mathieson last winter, he was desperately trying to find work. Mathieson, then 27, had been going to business school before he went to prison. When he got out, he went on job interviews. When the question about criminal history inevitably came up, he tried to stress to potential employers that he’d changed. But they still wanted to know about his conviction, and why he’d been in prison. It usually turned out badly.

“I told her about my conviction, and she wanted me to go deeper into what happened,” he told me, describing one interview in particular. “When I explained that I shot somebody in the back of the head, she didn’t want anything to do with me anymore.”

So-called ban-the-box policies—which prevent employers from asking about a candidate’s criminal history until later on in the hiring process—aim to help people like Mathieson more easily enter the labor market. President Obama “banned the box” on federal-government employment applications last year, and as of December 2015, 24 states and the District of Columbia have required employers to ban the box in some form.

But banning the box may actually be hurting some of the exact groups of people it was designed to help, according to a few new studies. In a recent paper from the National Bureau of Economic Research, Jennifer L. Doleac of the University of Virginia's Frank Batten School of Leadership and Public Policy and Benjamin Hansen of the University of Oregon looked at how the implementation of ban-the-box policies affected the probability of employment for young, low-skilled, black and Hispanic men. They found that ban-the-box policies decreased the probability of being employed by 5.1 percent for young, low-skilled black men, and 2.9 percent for young, low-skilled Hispanic men.

That’s because, they say, when employers cannot access an applicant’s criminal history, they instead discriminate more broadly against demographic groups that are more likely to have a criminal record. The paper indicated that this type of discrimination is especially prevalent in the Northeast, Midwest, and West, where there is a larger pool of non-black applicants to choose from. In the South, because such a large proportion of job applicants are black, the opportunity to discriminate is reduced, the paper finds. “There is rapidly-increasing evidence that [banning the box] has unintentionally done more harm than good when it comes to helping disadvantaged job-seekers find jobs,” they write.

The researchers crunched data for more than 855,000 men ages 25 to 34, 60 percent of whom are classified as low-skilled, meaning they didn’t have a college degree. Nearly half of the young, low-skilled men in the sample lived in areas with ban-the-box policies as of December 2014. The study calculated the likelihood that these men would be employed by looking at the average employment probability for men of the same race and ethnicity in the metro area, the employment trend for that ethnic group, and any unusual economic patterns in the region. They then compared that probability of employment  to the percentage of people from each group who actually were employed, according to data from the Current Population Survey (CPS), comparing and contrasting areas that introduced ban-the-box policies. In ban-the-box areas, the researchers theorize, employers are less likely to interview young, low-skilled black men because those groups are more likely to include ex-offenders. They instead focus on hiring groups made up of men they believe are less likely to have gone to prison, they say.

Their conclusion, that banning the box may have some substantial, unintended consequences, has been backed up by other research, too. In another study, Amanda Y. Agan of Princeton University and Sonja B. Starr of the University of Michigan Law School submitted thousands of fake job applications from young, low-skilled men of random races and criminal histories in New York and New Jersey, where ban-the-box policies had recently been introduced. And in a separate paper, Starr used CPS data from between 2004 and 2014 to measure how banning the box affected government employment rates. Her results also suggest that black men ages 18 to 64 were hurt by these policies. Overall, their study found that before ban the box, white applicants were called back slightly more often than black applicants were; after ban the box, white applicants were called back six times more often than black applicants were. White ex-offenders were actually helped by the rule, they found, possibly because employers assumed white applicants were unlikely to have criminal histories.

When employers have less information about an applicant, they discriminate against minorities, research suggests. For example, when employers are prevented from doing credit checks on potential employees, the likelihood of black applicants being hired is reduced by between 7 and 16 percent, one study found. When employers have more information, though, they are actually more likely to hire minorities. One study found that black employment rates actually increased, by between 7 and 30 percent, when employers require drug tests for employees. And another found that when firms conducted criminal background checks, the last hire was 37 percent more likely to be a black man.

These findings may speak more to the biases of employers than to the fundamental flaws of policies that try to help black and Latino men find jobs after getting out of prison. Still, it may prove difficult to overcome these biases in a society that has incarcerated its young black men at increasing rates. According to the NAACP, one in three black men born today can expect to spend some time in prison during their lifetime. As long as that remains true, weeding out such hiring discrimination won’t be easy.

To be sure, there are plenty of programs aimed at helping young men find employment once they get out of prison. There are nonprofits that help ex-offenders with temporary employment, at the same time reducing recidivism and increasing employment rates. Finding ex-offenders a steady place to live can also help them more easily find employment and help them build a sense of community after incarceration. But failure rates are still high, even for the most determined ex-offenders. That’s in part because no matter how committed former convicts are to finding gainful employment, employers remain prejudiced, and a criminal record is still a very heavy weight to bear.

Perhaps the most effective way to help young black men find work would be to figure out how to incarcerate them less in the first place. There may already be some progress in that arena, according to Keith Humphreys of The Washington Post, who writes that there are signs that black incarceration may finally be starting to decrease. Accelerating that trend may be the best hope of changing the discrimination that keep so many young black men out of the labor market, and living in cycles of poverty.