February 15, 2020

Flawed science? Two efforts launched to improve scientific validity of psychological test evidence in court

There’s this forensic psychologist, we’ll call him Dr. Harms, who is infamous for his unorthodox approach. He scampers around the country deploying a bizarre admixture of obscure, outdated and unpublished tests that no one else has ever heard of.

Oh, and the Psychopathy Checklist (PCL-R). Dr. Harms never omits that. To him, everyone is a chillingly dangerous psychopath. Even a 30-year-old whose last crime was at age 15.

What’s most bizarre about Dr. Harms’s esoteric method is that he gets away with it. Attorneys may try to challenge him in court, but their protests usually fall flat. Judges rule that any weaknesses in his method should go to the “weight” that jurors give Dr. Harm’s opinions, rather than the admissibility of his tests.

Psychological tests hold a magical allure as objective truth. They retain their luster even while forensic science techniques previously regarded as bulletproof are undergoing unprecedented scrutiny. Based in large part on our briefcases full of tests, courts have granted psychologists unprecedented influence over an ever-increasing array of thorny issues, from future dangerousness to parental fitness to refugee trauma. Behind the scenes, meanwhile, a lucrative test-production industry is gleefully rubbing its hands all the way to the bank.

In other forensic “science” niches such as bite-mark analysis and similar types of pattern matching that have contributed to wrongful convictions, appellate attorneys have had to wage grueling, decades-long efforts to reign in shoddy practice. (See Radley Balko's The Cadaver King and the Country Dentist for more on this.) But leaders in the field of forensic psychology are grabbing the bull by the horns and inviting us to do better, proposing novel ways for us to self-police.

New report slams "junk science” psychological assessments

In one of two significant developments, a group of researchers today released evidence of systematic problems with the state of psychological test admissibility in court. The researchers' comprehensive survey found that only about two-thirds of the tools used by clinicians in forensic settings were generally accepted in the field, while even fewer -- only about four in ten -- were favorably reviewed in authoritative sources such as the Mental Measurements Yearbook.

Despite this, psychological tests are rarely challenged when they are introduced in court, Tess M.S. Neal and her colleagues found. Even when they are, the challenges fail about two-thirds of the time. Worse yet, there is little relationship between a tool’s psychometric quality and the likelihood of it being challenged.

Slick ad for one of a myriad of new psych tests.
“Some of the weakest tools tend to get a pass from the courts,” write the authors of the newly issued report, "Psychological Assessments in Legal Contexts: Are Courts Keeping 'Junk Science' Out of the Courtroom?”

The report, currently in press in the journal Psychological Science in the Public Interest, proposes that standard batteries be developed for forensic use, based on the consensus of experts in the field as to which tests are the most reliable and valid for assessing a given psycholegal issue. It further cautions against forensic deployment of newly developed tests that are being marketed by for-profit corporations before adequate research or review by independent professionals.

"Life or death" call to halt prejudicial use of psychopathy test

In a parallel development in the field, 13 prominent forensic psychologists have issued a rare public rebuke of improper use of the controversial Psychopathy Checklist (PCL-R) in court. The group is calling for a halt to the use of the PCL-R in the sentencing phase of death-penalty cases as evidence that a convicted killer will be especially dangerous if sentenced to life in prison rather than death.

As I’ve reported previously in a series of posts (here and here, for example), scores on the PCL-R swing wildly in forensic settings based on which side hired the expert. In a phenomenon known as adversarial allegiance, prosecution-retained experts produce scores in the high-psychopathy range in about half of cases, as compared with less than one out of ten cases for defense experts.

Research does not support testimony being given by prosecution experts in capital trials that PCL-R scores can accurately predict serious violence in institutional settings such as prison, according to the newly formed Group of Concerned Forensic Mental Health Professionals. And once such a claim is made in court, its prejudicial impact on jurors is hard to overcome, potentially leading to a vote for execution.

The "Statement of Concerned Experts," whose authors include prominent professionals who helped to develop and test the PCL-R, is forthcoming from the respected journal Psychology, Public Policy, and Law.

Beware the all-powerful law of unintended consequences

This scrutiny of how psychological instruments are being used in forensic practice is much needed and long overdue. Perhaps eventually it may even trickle down to our friend Dr. Harms, although I have a feeling it won't be before his retirement.

But never underestimate the law of unintended consequences.

The research group that surveyed psychological test use in the courts developed a complex, seemingly objective method to sort tests according to whether they were generally accepted in the field and/or favorably reviewed by independent researchers and test reviewers.

Ironically enough, one of the tests that they categorized as meeting both criteria – general acceptance and favorable review – was the PCL-R, the same test being targeted by the other consortium for its improper deployment and prejudicial impact in court. (Perhaps not so coincidentally, that test is a favorite of the aforementioned Dr. Harms, who likes to score it high.)

The disconnect illustrates the fact that science doesn’t exist in a vacuum. Psychopathy is a value-laden construct that owes its popularity in large part to current cultural values, which favor the individual-pathology model of criminal conduct over notions of rehabilitation and desistance from crime.

It’s certainly understandable why reformers would suggest the development of “standard batteries … based on the best clinical tools available.” The problem comes in deciding what is “best.”

Who will be privileged to make those choices (which will inevitably reify the dominant orthodoxy and its implicit assumptions)?

What alternatives will those choices exclude? And at whose expense?

And will that truly result in fairer and more scientifically defensible practice in the courtroom?

It’s exciting that forensic psychology leaders are drawing attention to the dark underbelly of psychological test deployment in forensic practice. But despite our best efforts, I fear that equitable solutions may remain thorny and elusive.

The survey of forensic test use in court, in press in the journal Psychological Science in the Public Interest (the journal of the Association for Psychological Science) is open-access and available online (HERE). A brief review of the new study is available on the APS website (HERE).

The critique of the PCL-R in capital sentencing can be requested from the first author, David DeMatteo. The abstract is HERE. Supplemental materials can be found HERE. DeMatteo is a co-author of the new book, Becoming a Forensic Psychologist, of potential interest to some of this blog's readers.

1 comment:

lois@loisbernardlcsw.com said...

Great article. Not a forensic psychologist but always wondered about validity of the Hare test.