The low point for expert witnesses in courts in Australia can be easily identified as the time of the Lindy Chamberlain trial in the Northern Territory about 20 years ago. In that trial a so-called expert witness claimed that the spray pattern of a substance used to reduce the sound in a car was foetal blood from the deceased Chamberlain child Azaria. The mother, Lindy, was convicted of murder and sentenced to life imprisonment, but subsequently acquitted after many other hearings.
The reliability and value of expert witness testimony is again being discussed in relation to the trial of David Eastman for the murder of AFP Assistant Commissioner Colin Winchester. I will not elaborate on my personal opinion about this case here.
However, as the broader subject of expert witnesses, (who they are, how they are identified as experts and their precise role in the courts) is not fully understood by the man in the street, it may be helpful to address these issues.
Before I explore the details of these questions, in the interests of transparency I should explain that, quite unexpectedly, I found myself classified by the courts in both NSW and Victoria as an expert witness.
This came about as an indirect result of the fact that I spent three years full-time as the Head of Research for the Royal Commission into Aboriginal Deaths in Custody. Some years after the Royal Commission there was a tragic episode in a new private prison in Victoria in which there were four deaths in six months.
These facts tended to reinforce the public belief that private prisons were more dangerous than prisons managed by the government. The Victorian coroner convened a public hearing into these deaths.The coroner was particularly interested in the belief about private prisons being more dangerous but also the belief that publicity about suicides might provoke others to attempt suicide.
One of the legal teams representing the private company which managed the prison in which the four deaths had occurred invited me to appear as a witness.
I must confess I did not fully understand the difference between an ordinary witness and an expert, but after I was cross-examined for some time (I think in an attempt to discredit me) the coroner said he would accept me as an expert. After that, the questioning I faced was much less aggressive and went on for the best part of the day.
I was able to explain that, contrary to public belief, in Australia as a whole private prisons had fewer deaths per 1000 prisoners than did government prisons. The belief had come about because the media had given greater prominence to deaths in private prisons and that belief persisted long after the coronial hearing and long after I had published an article in an academic journal which showed the public view was wrong.
After that Victorian case I was invited to provide expert witness evidence in about a dozen civil cases in which either police or prison officers were alleged to have failed to provide an appropriate level of duty of care to persons in their custody. In all of these cases I typically received by special delivery a very large bundle of written material, quite often in a disordered condition. My job was to read all of the material and write a report before the actual appearance in court, but most often the matter was resolved by negotiation between lawyers for both parties and I was not required to appear.
For the first five or six cases I was retained by the law firm engaged by the plaintiff (most often the relatives of a person who had been injured or died while in custody) but after some unhappy incidents in which I found that the law firms were reluctant, or extremely slow, to pay the agreed fees I joined a private company established by a university to offer expert opinion services in a wide range of different subject areas. That arrangement was preferable for me as the company handled all of the money side of any engagements, and it also provided professional liability insurance for its experts.
I also learned from this company that expert witnesses now have a code of conduct which must be strictly followed. This makes it clear that the paramount duty of the expert witness is to the court and not to either party in the proceedings, regardless of who pays his or her fees. Furthermore, an expert witness must abide by any direction of the court to confer with other expert witnesses on opinions expressed in court and if ordered prepare a joint report specifying where agreement has been reached and where it has not.
The expert witness today is not an advocate for the client of a lawyer, but an impartial person, who has appropriate qualifications and experience and is permitted by the court to express opinions as well as relate facts.
The days of lawyers ''expert shopping'' for witnesses who will help their side of the case should be well and truly a thing of the past.
I am confident that in most subject areas where expert witnesses are called, such as hand-writing, finger-printing and DNA evidence, there are unlikely to be significant differences of opinion between experts, but in the social sciences, such as psychology, psychiatry and criminology, differences of opinion are still likely to occur, but with the move towards a more professional and objective approach which has developed over the past few years these sorts of disputes should be much less common than they were in the past.
David Biles is a Canberra-based consultant criminologist.
