What constitutes bias in an expert witness?

Posted on 01/01/2009 · Posted in Expert Information

Who does an expert witness owe a duty to?

This is probably the most important aspect of an expert’s work. His duty is to the court and he has to maintain his independence at all times. This has been enshrined in the court rules in many parts of the world.

Nothing is a waste of time if you use experience wisely.”
Auguste Rodin

Originally the duties of an expert were covered in a court case, which is now known as the Ikarian Reefer rules. This was follows a judgement by Mr. Justice Cresswell in National Justice Compania Naviera SA v Prudential Assurance Company Limited in 1993.

Since then various legal jurisdictions have produced detailed rules such as:

There are also some places that still have no rules, but in such cases it then becomes common to adopt the rules from a known jurisdiction, usually the English ones. One such place is Ireland, which although has an established basis on which expert evidence is given, there are not formal rules. It is anticipated that they will institute their own before too long.

Biases may be conscious and unconscious. An expert’s partiality may be implicated for the following reasons:

  • Failure to disclose previous correspondence with either party including private or business relationships that are external from the dispute at hand. This is usually a form of conscious bias.
  • An expert that alters his or her view throughout the case and is swayed by the opinion of other experts.
  • Experts may even be challenged on the methodology that they use to arrive at their conclusions. Whilst this form of bias is usually unconscious, it merely suggests that an expert’s evidence will not stand up against conflicting evidence or testing and is generally perceived as flawed by their intellectual community. In the United States the terminology used for an expert that is challenged on these grounds is a Daubert challenge, but courts elsewhere may use different nomenclature.

Court recommended measures for mitigating expert bias include:

  • Probative questions during cross-examination, an expert’s opinions should be able to stand up to the questions of other experts during this stage.
  • Concurrent expert evidence or ‘hot-tubbing’, a method commonly used in Australia; is a discussion chaired by a judge, whereby the various experts, and the judge engage in a co-operative endeavour to identify the issues of the case and arrive where possible at a common resolution of them. Due to the fact that throughout this process the experts are autonomous from their clients, but moreover responding to the judge, their duty to the court is upheld. The other great benefit of concurrent evidence or ‘hot-tubbing’ is that experts are able to respond directly to one another. In complex intellectual fields, where technical points may be disputed this helps to reduce the margin for bias within methodologies, as experts can clearly discuss why one methodology should be favoured over another.

Please do not expect an expert to support the case irrespective of the facts, it will avoid disappointment. Although he will not be part of the legal team who is arguing for a litigation party – he is probably a really asset if he is used correctly.

Read the next article – Reduce your litigation costs by hiring an expert witness?

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Expert Evidence is a professional firm concentrating on the four main areas of dispute resolution; acting as expert witnesses in financial litigation, mediation, arbitration and adjudication. The firm has a civil, criminal and international practice and has advised in many recent cases. Areas of specialisation include banking, lending, regulation, investment, and tax.

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Disclaimer please confirm any of the above views with your solicitor. Expert Evidence takes no responsibility or provides any guarantee that the views above are correct for your particular case or jurisdiction.