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Expert witness bias largely unchecked in Australian courts

22 June 2020
Limited codes of conduct can't curtail it
Transforming procedure is a way to enhance objectivity in our courts, new research shows. Led by Dr Jason Chin, it also explores the failings of the legal system status quo with regard to expert witnesses.

Did you know that there is almost no empirical research to guide judges in how they manage potentially biased expert evidence, like forensic science?

A recent paper, ‘The New Psychology of Expert Witness Procedure’, begins to redress this. Published by Sydney Law Review, the paper looks at the procedures intended to ensure that expert witnesses are impartial, and finds that they are inadequate.

The authors, Dr Jason Chin (University of Sydney Law School), Associate Professor Mehera San Roque (UNSW) and LLB candidate Rory McFadden (University of Queensland) propose that law could harness the psychology of ethical behaviour to help manage experts, and therefore maintain public trust in our court system.

“Many of the concerns about expert witness partisanship merged with fears that ‘junk science’ was finding its way into courtrooms, presented by unscrupulous experts, willing to tailor their evidence to the needs of their instructing client,” lead author, Dr Jason Chin said.

“Despite this, Australian courts have typically refrained from demanding that expert evidence be demonstrably reliable.”

Decoding codes of conduct

Focusing on Australian criminal law, the authors note that procedures intended to ensure expert witness impartiality, such as codes of conduct, are not only recent introductions, but are limited in their application.

“Only in Victoria, and only very recently, has a Practice Note (a document detailing procedural guidelines) been developed specifically for criminal trials,” Dr Chin said.

Even when procedures are in place, they tend to overlook more subtle forms of bias, such as unconscious contextual bias (when irrelevant details of a case affect an expert’s judgment).

How behavioural ethics can reveal bias

Behavioural ethics is a relatively new field of research that studies how people behave when confronted with ethical dilemmas.

“Behavioural ethics illuminates the processes that encourage expert witnesses to overstate their findings and downplay the limits of their expertise. It explains how they can do these things and still see themselves as upstanding actors in their field,” Dr Chin explained.

One such process, ‘ethical fading’, occurs when people operate on autopilot, losing sight of the ethical component of what they are doing. Making the ethical component clear can correct for this. For example, signing an honour code or reciting the Ten Commandments has been found to substantially reduce cheating.

Another process occurs when ethical criteria are flexible or unclear, so that people can stray from them without jeopardising their sense of morality.

Further processes include ethical blind spots (when people tend to see themselves as objective and others as biased) and slippery slopes (where one wrongdoing leads to another, to conceal the initial one).

Using behavioural ethics to change codes, culture

The authors propose that courts should embrace behavioural ethics to counter expert witness bias. One way they can do this is by modifying codes of conduct to engage experts’ moral compasses.

The authors argue that codes should:

  • remind the expert of his or her duty to the court
  • interrupt the typical script and any favourable social comparisons that the expert may make -for example, by comparing him or herself to an unscrupulous expert
  • make it clear that the expert is solely responsible for his or her opinion (to avoid diffusion of responsibility).

With behavioural ethics concepts in mind, court culture, too, can be reformed to enhance expert witness objectivity.

“There is a pervasive court culture [in common law jurisdictions] that tolerates ‘experts’ overstating their claims and does not effectively enforce codes of conduct,” Dr Chin said.

For example, an inquiry in Ontario, Canada into the wrongful convictions that resulted from the work of forensic pathologist Dr Charles Smith concluded that Dr Smith ‘believed that his role was to act as an advocate for the Crown and to “make a case look good”.’

In Australia, the trend has been for courts to take codes of conduct increasingly less seriously. To date, the authors are only aware of one Australian court decision that excluded an expert for failing to follow a code of conduct.

The authors conclude that, despite its past failings, expert witness procedure is a key tool for tackling expert witness bias: “When designed with reference to effective scientific procedural safeguards, and enthusiastically enforced by courts, it may provide serious benefits to the trial process.”

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