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Expert witnesses on what causes bias in other expert witnesses

Monday, December 17, 2012
posted by Rita Handrich

Mock jurors see themselves as nobler than their neighbors. We often hear from mock jurors that they believe “other people called for jury duty” in their venue might be biased against case parties but they, themselves, most assuredly are not! It’s a self-protective measure many of us use and so it’s a way we can ask a question (e.g., it’s about other people, not you!) and get more honest feedback regarding general attitudes in the venire.

Researchers from Massachusetts (the Beth Israel Deaconess Medical Center and the Dare Institute) recently used the same strategy with expert witnesses to find out reasons “other expert witnesses” might be biased. The researchers went to a meeting of the American Academy of Psychiatry and Law and asked 46 attendees at a workshop on “twilight issues” (e.g., “attorney-expert matters not often openly addressed”) to complete a questionnaire as to what situations they would see as most potentially biasing for an expert witness.

Most of the research participants were psychiatrists and the remainder were psychologists as well as a few miscellaneous participants. On average, they had been in forensic practice for more than 11 years and had about 49 forensic cases per year (again, on average).

While there were several aspects to the study, we will focus here on what variables these expert witnesses saw as the biggest threat to unbiased expert witness testimony. What the experts thought may surprise you.

Most biasing: The experts thought testimony would be most biased in cases the expert turned down due to their own personal experiences. (That makes good sense.) The second most biasing condition was identified as when experts exclusively testify for one side (either plaintiff/prosecution always or defense always).

Least biasing: The experts thought testifying as an expert witness while also serving as treating professional was not biasing. This has long been held to be a significant issue in expert objectivity and the researchers questioned why this would not have emerged as a significant source of bias.

Finally, the researchers call for a similar study to be done of jury-eligible citizens to see if similar attitudes (to the expert’s attitudes) toward expert testimony are shown. They point out that judges and attorneys often “informally say that experts rarely have any effect on the case outcome”.

In our experience, jurors are often skeptical of experts and want to be reassured that testifying experts are not simply “hired guns”. In medical testimony, they prefer treating experts (they seem to know the litigant better) and they want “real people” rather than academics.

It would be interesting to see the research expanded to consider experts in other fields, such as engineering or economics, and factors enhancing their influence.

***We appreciate being included in the ABA Blawg 100 for the third year in a row! If you like our blawg, take a minute to vote for us here (under the Trial Practice category). Thanks! Doug and Rita***

Commons ML, Miller PM, Li EY, & Gutheil TG (2012). Forensic experts’ perceptions of expert bias. International Journal of Law and Psychiatry PMID: 23046867

Image: Photo of questionnaire items used in study.

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