Jonathan Karas QC outlines the desired qualities of expert witnesses
The law puts exacting standards on expert witnesses. The standards are high. This ensures that the courts can put trust in the experts but also that the public can have faith in the legal system in which they play a part.
The law and perceptions
To that end, expert witnesses (i) must be and be seen to be impartial and (ii) must provide independent assistance and unbiased opinions (National Justice Compania Naviera SA v Prudential Assurance Co Ltd (The Ikarian Reefer) [1993] 2 Lloyd’s Rep 68). The first requirement deals with the position of the expert. The second with what the expert must do in that position. There seems to be no more than a semantic difference between “impartiality” and an absence of bias.
The dangers of bias
Bias disqualifies a person from acting as an expert witness. The reason is that “[b]ias operates in such an insidious manner that the person alleged to be biased may be quite unconscious of its effect” (per Lord Woolf in R v Gough [1993] HL 646
