Adversarial allegiance: Frontier of forensic psychology research

A colleague recently commented on how favorably impressed he was about the open-mindedness of two other forensic examiners, who had had the courage to change their opinions in the face of new evidence. The two had initially recommended that a man be civilly committed as a sexually violent predator, but changed their minds three years later .

My colleague's admiration was short-lived. It evaporated when he realized that the experts’ change of heart had come only after they switched teams: Initially retained by the government, they were now in the employ of the defense.

"Adversarial allegiance" is the name of this well-known phenomenon in which some experts' opinions tend to drift toward the party retaining their services. This bias is insidious because it operates largely outside of conscious awareness, and can affect even ostensibly objective procedures such as the scoring and interpretation of standardized psychological tests.

Partisan bias is nothing new to legal observers, but formal research on its workings is in its infancy. Now, the researchers spearheading the exploration of this intriguing topic have put together a summary review of the empirical evidence they have developed over the course of the past decade. The review, by Daniel Murrie of the Institute of Law, Psychiatry and Public Policy at the University of Virginia and Marcus Boccaccini of Sam Houston State University, is forthcoming in the Annual Review of Law and Social Science.

Forensic psychologists’ growing reliance on structured assessment instruments gave Murrie and Boccaccini a way to systematically explore partisan bias. Because many forensic assessment tools boast excellent interrater reliability in the laboratory, the team could quantify the degradation of fidelity that occurs in real-world settings. And when scoring trends correlate systematically with which side the evaluator is testifying for, adversarial allegiance is a plausible culprit.

Daniel Murrie

Such bias has been especially pronounced with the Psychopathy Checklist-Revised, which is increasingly deployed as a weapon by prosecutors in cases involving future risk, such as capital murder sentencing hearings, juvenile transfer to adult courts, and sexually violent predator commitment trials. In a series of ground-breaking experiments, the Murrie-Boccaccini team found that scores on the PCL-R vary hugely and systematically based on whether an expert is retained by the prosecution or the defense, with the differences often exceeding what is statistically plausible based on chance.

Systematic bias was also found in the scoring of two measures designed to predict future sexual offending, the popular Static-99 and the now-defunct Minnesota Sex Offender Screening Tool Revised (MnSOST-R).

One shortcoming of the team’s initial observational research was that it couldn’t eliminate the possibility that savvy attorneys preselected who were predisposed toward one side or the other. To test this possibility, two years ago the team designed a devious experimental study in which they recruited forensic psychologists and psychiatrists and randomly assigned them to either a prosecution or defense legal unit. To increase validity, the experts were even paid $400 a day for their services.

Marcus Boccaccini

The findings provided proof-positive of the strength of the adversarial allegiance effect. Forensic experts assigned to the bogus prosecution unit gave higher scores on both the PCL-R and the Static-99R than did those assigned to the defense. The pattern was especially pronounced on the PCL-R, due to the subjectivity of many of its items. ("Glibness" and "superficiality," for example, cannot be objectively measured.)

The research brought further bad tidings. Even when experts assign the same score on the relatively simple Static-99R instrument, they often present these scores in such a way as to exaggerate or downplay risk, depending on which side they are on. Specifically, prosecution-retained experts are far more likely to endorse use of "high-risk" norms that significantly elevate risk.

Several somewhat complimentary theories have been advanced to explain why adversarial allegiance occurs. Prominent forensic psychologist Stanley Brodsky has attributed it to the social psychological process of in-group allegiance. Forensic psychologists Tess Neal and Tom Grisso have favored a more cognitive explanation, positing heuristic biases such as the human tendency to favor confirmatory over disconfirmatory information. More cynically, others have attributed partisan bias to conscious machinations in the service of earning more money. Murrie and Boccaccini remain agnostic, saying that all of these factors could play a role, depending upon the evaluator and the situation.   

One glimmer of hope is that the allegiance effect is not universal. The research team found that only some of the forensic experts they studied are swayed by which side retains them. Hopefully, the burgeoning interest in adversarial allegiance will lead to future research exploring not only the individual and situational factors that trigger bias, but also what keeps some experts from shading their opinions toward the retaining party.

Even better would be if the courts took an active interest in this problem of bias. Some Australian courts, for example, have introduced a method called "hot tubs" in which experts for all of the sides must come together and hash out their differences outside of court. 

In the meantime, watch out if someone tries to recruit you at $400 a day to come and work for a newly formed legal unit. It might be another ruse, designed to see how you hold up to adversarial pressure.

* * * * *

The article is: Adversarial Allegiance among Expert Witnesses, forthcoming from The Annual Review of Law and Social Science. To request it from the first author, click HERE. 

Related blog posts:

• Remarkable experiment proves pull of adversarial allegiance (March 5 2013)  
• Psychopathy: A Rorschach test for psychologists? (March 25, 2011) 
• "Hot tubbing": Counterbalance for expert partisanship? (Aug. 11, 2008)

Recommended summer reading

Among a bumper crop of engaging new books, here are a few that stand out as especially relevant to forensic psychologists interested in popular culture: 

Murder as public spectacle

If you want to understand the nature of murder and its resolution in U.S. inner cities, look no further than L.A. Times reporter Jill Leovy's Ghettoside: A True Story of Murder in America. Leovy embedded herself with detectives in one South Los Angeles precinct to discover the gloomy truth: When the government does not provide strong, centralized justice, people will take the law into their own hands … with tragic results.

Sexual assault, unpunished

With upwards of one in five women raped in their lifetimes, rape is much more common than most people realize, its most frequent victims college-aged women. So, why are so few sexual assaults ever reported to authorities? You will understand why after reading bestselling journalist Jon Krakauer's Missoula: Rape and the Justice System in a College Town. This superbly researched account traces the ordeals of a cluster of young college women with the audacity to buck the good-old-boys system in search of justice.

A culture of shaming

And finally, what's up with the culture of public shaming that seems to be strangling popular culture, with shame-laced posts regularly going viral on Twitter and other social media sites? Jon Ronson (whom you'll recall from his quirky bestseller, The Psychopath Test) confronts this nasty epidemic in his engaging new book, So You've Been Publicly Shamed. 

Quick reads.
Cutting-edge topics.
Recommended.

Science reporter delves into shadowy realm of civil commitment

Wayne Hicks and Hersey Lelaind. Illustration by Jenny Chang.

"Hersey Lelaind knew he was in trouble -- just not how much trouble. He and a housemate had been on a drive, and Lelaind had been smoking pot. When they returned to their home in Vacaville, California, the sheriff’s department was waiting…. 

"That was in 2006, when Lelaind was 26 years old. He’s been kept under lock and key ever since. His problem wasn’t the drug bust itself. But the bust prompted the authorities to review Lelaind’s checkered past. As a teenager, he had been convicted for sexual abuse against a minor -- and had served his time. 

"That fact, along with other aspects of his criminal and life history, were entered into the 'Static-99,' a little-known but highly influential questionnaire that critics contend is being tragically misused. The test spit out a score that set him on the path to being locked up in a state psychiatric facility. Why? Because he might commit another crime in the future. He doesn’t know if he will ever be released."

So begins an expose on the U.S. civil commitment industry by Peter Aldhous, an award-winning science writer. Writing for Buzzfeed, Aldhous traces the stories of both Hersey Lelaind, an African American man from San Francisco, and Wayne Hicks, a gay man from the Deep South, to illustrate the life-shattering consequences of getting a bad score on a badly flawed actuarial risk instrument.

The dramatically different outcomes for Lelaind and Hicks underscore the hit-or-miss nature of risk assessment, where the difference between freedom and a life behind bars can be something as random as which evaluator is assigned to the case or what risk tool that evaluator chooses to employ.

The featured narratives hold special significance for me, because I was retained as an expert in each case. Hicks was set free after the federal prosecutor read my report, while Lelaind went to trial and was civilly committed -- despite the fact that he is neither a pedophile nor a rapist.

Word on the street is that the Buzzfeed piece, "These 10 Questions Can Mean Life Behind Bars," is getting a lot of, well, buzz. I encourage readers to share it widely. Hopefully, it can help to foster public and professional dialogue on the implicit biases undergirding the civil commitment enterprise.