Below is an excerpt from a well known expert witness in custody disputes. The information provided herein helps you understand how to bolster or attack an expert in a custody case. These methods are employed by our firm in achieving great results for our clients.

Inductive reasoning, the “bottom-up” problem-solving approach discussed in our last Brief, characterizes the process by which psychologists conduct forensic evaluations: directed by specific referral questions, they gather data through their methods, reason from the data, and arrive at their conclusions and opinions.

This approach offers opportunities for convincing direct-exams and sharp cross-exams of the evaluator-expert. The key? Focus on the expert’s reasoning—the step that links the expert’s data to her conclusions and opinions. Although experts purport to bring the “knowledge and experience of their discipline” to the stand, they are vulnerable to the same reasoning pitfalls that affect us all: biased thinking that finalizes judgments too quickly. Competent expert testimony acknowledges and manages potential reasoning problems. Incompetent testimony glosses over, if not denies, those problems.

Expose the expert’s reasoning that supports her testimony by focusing on two caselaw and research-based lines of questions: Did the expert actively consider reasonable alternative explanations of her data? Is the expert aware of cognitive biases that may compromise her opinions?

The most effective strategy for experts to manage reasoning problems that could infect their opinions is to actively consider reasonable alternative explanations of their data until the best explanation survives—an effortful, critical thinking approach to which experts must commit themselves. Merely acknowledging that alternative explanations exist without purposefully marching the data through those explanations is insufficient. Psychologist Daniel Kahneman characterizes the effort that distinguishes the active from the passive approach: “Sustaining doubt is harder work than sliding into certainty.”

Law and psychology confirm the active strategy’s importance. Caselaw notes that considering alternative explanations is one indication of an opinion’s reliability. Cognitive research shows that an active strategy “breaks the inertia” that sets in if the expert is pulled by a particular view of the case.

Use this key principle, supported by the Brief Quotes below, when you examine experts by deposition or in court. For example, when an expert testifies that her data supports that a child has been abused or that a plaintiff has not sustained emotional trauma, ask the expert to list all other reasonable explanations she considered of the data and how she actively addressed each explanation before she settled on her opinions. Her answers will reveal the quality and extent of the reasoning that supports her opinions.

Our next few Briefs will address the second line of questions to expose the expert’s reasoning: cognitive biases that may compromise experts’ opinions.

References: Daniel W. Shuman & John A. Zervopoulos, Empathy or Objectivity: The Forensic Examiner’s Dilemma? 28 Beh. Sc. & Law 585, 595 (2010) (presents a model for managing biases by actively considering reasonable alternative explanations); John A. Zervopoulos, Confronting Mental Health Evidence 77 (2008).

Brief Quotes
• “Courts both before and after Daubert have found other factors relevant in determining whether expert testimony is sufficiently reliable to be considered by the trier of fact. These factors include: . . . (3) Whether the expert has adequately accounted for obvious alternative explanations.” Fed. R. Evid. 702 advisory committee’s note.

• “Forensic practitioners seek to maintain integrity by examining the issue or problem at hand from all reasonable perspectives and seek information that will differentially test plausible rival hypotheses.” American Psychological Assn., Specialty Guidelines for Forensic Psychology, Guideline 9.01 (2011).
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John A. Zervopoulos, Ph.D., J.D., ABPP is a board certified forensic psychologist and lawyer who directs PsychologyLaw Partners, a forensic consulting service. Dr. Zervopoulos—combining the psychological and legal perspectives—assists lawyers to organize, critique, and use psychology-related materials and evidence in their cases. He also authored Confronting Mental Health Evidence: A Practical Guide to Reliability and Experts in Family Law, published in 2008 by the ABA. Dr. Zervopoulos is online at www.psychologylawpartners.com and can be contacted at jzerv@psychologylawpartners.com or at 972-458-8007.

If you have any questions regarding complex custody cases please contact us at 505-880-8737.