Several new studies on so-called “ban the box” policies that block employers from discounting job applicants with criminal records have revealed another, even more extensive problem: deep-seated employer discrimination against African Americans.

Ban-the-box laws, which prevent employers from asking about criminal history on job applications, have passed in scores of cities, 24 states and the District of Columbia. The laws were intended to reduce the impact of US mass incarceration on hiring as individuals with a criminal record attempt to return to the workplace. Because African Americans are five times more likely than whites to be incarcerated, a major secondary goal of ban-the-box advocates is to reduce the effect of racial disparities in employment. Black unemployment has hovered at almost twice that for white Americans in the US.

But researchers who have scrutinized the policies have found that, regardless of whether employers ask about criminal history, African Americans face discrimination from employers with ingrained racial biases.

“The core problem raised by the studies is not ban-the-box but entrenched racism in the hiring process, which manifests as racial profiling of African Americans as ‘criminals’,” said researchers Beth Avery and Maurice Ensellem with the National Employment Law Project, in a new study released on Thursday.

Other studies released over the past few months have reached the similar conclusion that black Americans may be profiled as criminals. Another released in June sent out 15,000 fake job applications in states with ban-the-box laws – New York and New Jersey – before and after their respective laws took effect.

Amanda Agan of Princeton University and Sonja Starr of the University of Michigan found that there was a smaller increase in callbacks for low-skilled black and Hispanic men compared to whites in places where the reforms had been enacted.

The authors found that while the number of people with criminal backgrounds received more employer callbacks overall, the disparity between those given to whites and blacks had increased, with a 7% difference before, versus 45% after.

But the findings have split researchers on what exactly to do about it, with some saying that the new policies are exacerbating disparities in hiring, while others say it is underlying prejudice and not these laws that are to blame.

Professors Jennifer Doleac of the University of Virginia and Benjamin Hansen of the University of Oregon, suggested in a paper earlier this month that by removing data about the criminal histories of job applicants, employers were more likely to make assumptions about these people’s backgrounds. That in turn, the authors suggested, could lead to a reduction in the hiring of young black and Hispanic men because of racial bias by prospective employers.

Doleac, who is also a visiting fellow at the Brookings Institution, a Washington DC-based thinktank, said in a separate piece that ban-the-box had “done more harm than good”, and should be abandoned as a result.

But the NELP researchers, who support “fair-chance employment policies” such as ban-the-box, argue that the reform is a necessary but not sufficient policy response to structural causes of discrimination in the US.

The researchers questioned the methodology of the Doleac/Hanson study, but said that even if one were to accept those criticisms of “ban-the-box” provisions, it would “merely reinforce the need for stronger anti-discrimination law enforcement and further policy reforms to help eradicate the underlying discrimination, not a rejection of ban-the-box protections”.

The NELP researchers said the two studies underscored the need to push “for a more robust policy response to both boost job opportunities for people with records and tackle race discrimination in the hiring process”. But, they added, it would be a mistake to lay shortcomings at the foot of “ban-the-box” policies.

“Ban-the-box is working, both by increasing employment opportunities for people with records and by changing employer attitudes toward hiring people with records,” they said.

Asked about the criticism, Doleac agreed that “it’s possible that ‘ban the box’ would be a more effective policy in a world with less racial discrimination”. But, she added: “Our research considers its effects on employment in the world we actually live in.

“Laws can hide information, but they don’t prevent employers from caring about the information that’s hidden.” She added that this “typically hurts already-disadvantaged groups” because of how employers guess.