An ambitious new law in California taking aim at potential biases of prospective officers has raised questions and concerns among police officers and experts who fear that if implemented inadequately, the law could undermine its own mission to change policing and the culture of law enforcement.

The law, which was signed by Gov. Gavin Newsom (D) on Sept. 30, will expand the present screening requirements by mandating all law enforcement agencies conduct mental evaluations of peace officer candidates to identify both implicit and explicit biases against race, ethnicity, gender, religion and sexual orientation to exclude unfit recruits.

Experts, police unions and lawmakers agree on the value of identifying whether those who aspire to become officers carry considerable degrees of biases, yet it is the lack of clarity on what tools and measures will be used to look for implicit biases that is raising concerns and prompting questions.

“If police departments start to reject applicants because they have implicit biases there will be no one left to hire,” said Lorie Fridell, professor of criminology at the University of South Florida and founder of the Fair and Impartial Policing program, one of the most popular implicit-bias awareness trainings in the country.

Under the new law, the state Commission on Peace Officer Standards and Training (POST) will review and develop new regulations and screening materials to identify these potential explicit and implicit biases. It will be up to each agency in the state to determine how to administer them.

POST information officer Meagan Catafi would not say whether implicit association tests will be part of the new screenings, saying, “It is too premature at this point to know what will be assessed and used in our materials.”

Catafi said POST will be working with psychologists and law enforcement experts to incorporate these new required items to the current psychological screening manual, and they have until January 2022 to complete the process.

The law comes amid a moment of social upheaval where police departments across the country are facing scrutiny and increasing calls for accountability over cases of slayings of unarmed civilians and excessive use of force that disproportionately affects minorities.

This has prompted many agencies to ramp up efforts to identify racist and other discriminatory beliefs that could lead to destructive behavior, mostly by incorporating bias, diversity and inclusion training programs for active officers.

None of the experts interviewed by The Washington Post claimed to know of law enforcement agencies that screen for unconscious biases — those that people are unwilling or unable to identify — as a hiring standard. All of them, however, are either wary of such approach or advise against it.

“This is a tough one. What do you do if someone tests positive for racism?” Do you train them again? Do you fire them? There are a lot of unknowns about how this might look like,” Los Angeles Police Department Commander Ruby Flores, who is in charge of training, told The Post.

Flores also pointed out that under the new law “high quality applicants” could be inadvertently dismissed before being trained to manage their built-in biases, which, she said, all people have.

“My fear is that if this is not done thoughtfully and it is something that it is not all-inclusive, we may be inadvertently hurting the very people that we want to come in our department,” she added.

Fridell from the University of South Florida said even if a person has high levels of implicit associations for concepts such as Black individuals and crime does not mean the person will be a poor performing officer. “It is wholly unadvisable.”

Jerry Kang, professor at UCLA School of Law and a renowned expert on implicit bias, said while the new law recognizes the importance of talking about biased behavior among officers, “it worryingly assumes there is an easy way to identify emotional and mental conditions that include implicit bias on specific individuals.”

A shared concern among scholars is on the use of tools such as implicit association tests (IATs) — sometimes used in bias training — as a hiring tool or screening device due to the unreliability of its findings.

These types of evaluations, they say, do not necessarily predict future behavior or future beliefs as they are constantly relearned by individuals and supplied by society.

“I cannot scrub your brain because it will get dirty again in 24 hours. We relearn our biases every 24 hours, and implicit biases change only at a societal scale throughout time,” Kang said.

Seth W. Stoughton, an associate professor at University of South Carolina School of Law, said that even though he recognized California’s statute remains vague about what type of pre-screening materials will be used, he is skeptical of taking implicit bias evaluations like IATs, as benchmarks of deep-seeded beliefs that would lead to discrimination.

“My worry is that these will be mistaken as diagnostics, and that opens up a strong potential of misapplying the value or results of something like implicit associations tests,” Stoughton said.

Kang said implicit bias tests provide useful, yet inexact information, which he compared to weather forecasts, about a person’s beliefs and stereotypes at a certain moment, but they ought to be used as road maps to help law enforcement agencies develop better methods and procedures, rather than as individual hiring tools.

Another reason some experts doubt whether built-in bias assessment would work is that widespread IAT data shows most people in America have strong racial biases.

David Harris, a professor at the University of Pittsburgh School of Law who does implicit bias training, said IAT data show 88 percent of White people and up to half (48 percent) of Black people hold a preference for White people.

“This may explain patterns of behavior toward others groups like Blacks or dark-skinned people, but does not tell us which police officers will do what in any given situation,” Harris said, adding that social context is a significant factor that motivates behavior.

Harris said a better predictor of behavior would be to look at an officer’s track record on the job, and then use early intervention systems and training to manage and reduce bias.

But with recent reports emerging of extremists and white nationalists trying to infiltrate law enforcement, experts say there is renewed interest among agencies and lawmakers to find ways to better filter candidates.

The bill is part of several recent legislative breakthroughs, including a ban on chokeholds and the creation of an investigative unit within the Department of Justice to handle investigations of officer-involved shootings.

In 2015, Kamala D. Harris — then California’s attorney general — launched a statewide training program for law enforcement on implicit bias, and created a police task force to lead public dialogue on the issue.

To try to identify candidates who are unfit for the job, including those with discriminatory tendencies, most law enforcement agencies conduct extensive background checks and psychological tests that try to assess individual prejudices and levels of tolerance. Under California rules, all officer candidates are evaluated by a physician or psychologist and required to be found free of physical, emotional or mental conditions that would negatively affect their ability to exercise their powers. While potential biases are usually addressed in the applicant’s background checks and mental screenings, there are no specific tests to separately identify different types of bias.

These screenings vary agency to agency and often include review of social media postings for sexist or racist comments, interviews with acquaintances, past employers, family members and thorough mental evaluations.

An argument put forth by the California Police Chiefs Association during the Assembly vote last month was that the law imposes unnecessary work for POST, since its current psychological screening manual already includes bias assessment.

Brian Marvel, president of the Peace Officers Research Association of California (PORAC), which represents more than 77,000 members statewide, said the group supports any efforts to prevent problematic officers from joining the forces, but he underlined the need to have qualified professionals apply these evaluations to ensure fair treatment.

“When you are dealing with people there is no infallible process. We are hiring human beings from the community, and there is no way to find the perfect people because nobody is a saint. You just try to do the best you can,” Marvel said.

As the outcome of this new legislation remains to be seen, Flores of the Los Angeles police said it is important to place the police under greater examination.

“We are having an inward reflection, not only looking at ourselves at a mirror but looking at ourselves with a microscope because when you do that, you see things that you don’t want to see,” Flores said. “That is the challenging part, but I welcome it.”