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Be proficient in the science

22 November 2013

With this, my last column before Christmas, I want to explore some of the challenges litigators face with science, both in the context of investigating a case and ultimately challenging expert scientific evidence in court.

On reading the latest edition of the New Zealand Universities Law Review (the 50th anniversary edition) I noticed an outstanding article by Dr Yvette Tinsley on science in the criminal courts. Dr Tinsley’s article is a must read for all litigators and is full of gems that will hopefully dispel some of the myths of absolutism that for many surround forensic evidence in particular.

That article alone should instil confidence in litigators to explore and challenge more of the science that often swims around cases, civil and criminal alike.

Cases can often devolve into the litigation of science with expert against expert in a tug-of-war like battle to convince a judge or jury of the merits of their respective sides. In other cases, while not a “battle” per se, expert testimony can nonetheless mean the difference between a finding for or against a client.

I remember one case from my days as a court registrar that involved lengthy testimony of a paint analysis expert. His testimony focused on the issue of whether the stolen item at the centre of the alleged offending (an air compressor) was ever painted yellow and if so how long ago. Suffice it to say the Crown’s case was lost almost entirely due to the mind-numbingly boring nature of this evidence.

But let us not pretend that experts always manage the mental gymnastics of representing the objective truth of scientific wisdom over representing the side who has engaged them. Counsel rarely manage to maintain an objective and detached approach to their client’s case so expecting expert witnesses to do the same is, well, unrealistic.

Let us also not pretend that science is unmoved by ideology, or that it is not “subjective and value-laden, being imbued with social, political, historical, gendered and moral aspects” – a view cited, if not entirely supported, by Dr Tinsley.

Whether this is accurate or not, the key to both the effective use of and challenge to expert scientific evidence is for a litigator to be proficient in the science themselves. By this I do not mean merely understanding the opinion of your own expert, but actually understanding the applicable body of science itself.

There are, of course, many difficulties with this, not least of which the scientific background needed to not only understand the import of an opinion but to understand the science to such a level that one is able to directly challenge expert testimony in cross-examination.

However, a further and altogether more difficult proposition is for a litigator to also understand the nature of the science at play at the investigation stage of a case. Not knowing what you do not know is a condition that affects us all and gives rise to very real difficulties when one is presented with facts and figures as part of discovery that may appear absolute and irrefutable.

In such a case a lack of knowledge of fingerprint evidence, DNA analysis, forensic medicine and even scientific processes of institutions such as ESR for example, mean that litigators may be prone to accepting conclusions of apparent fact from the other side that are, quite simply, not worth the paper they are written on.

Conveniently some cases will from day one identify themselves as revolving around science.

The Gwaze murder case is one such example. In this case the expert medical and forensic evidence was that the deceased had likely died of asphyxiation or strangulation administered to keep her quiet while she was sodomised. The defence case was that there had been no such penetration or asphyxiation but that the deceased had died of an overwhelming and sudden sepsis that resulted from complications associated with congenital HIV.

In successfully defending Mr Gwaze in two jury trials, the expert medical knowledge of Jonathan Eaton QC was nothing short of astounding. However, as I say, Mr Eaton was on notice from day one that medical science was the primary matter in issue.

Not all cases are so clear. Without a background in forensics, for example, it is more difficult to identify areas of fruitful scientific examination not necessarily evident on the face of a case.

For example, the process of DNA analysis and the possibility of contamination within a lab have resulted in a number of gross miscarriages of justice around the world (suggested contamination exists in the Watson case in New Zealand).

So, too, problems associated with failure to adequately secure a crime scene (see Bain), ask the right questions at the right time in regards to blood and brain tissue analysis (Lundy) or the numerous cases in which fingerprint evidence was presented as entirely conclusive where in reality it was anything but.

Just as we are entirely comfortable with the statement that the law is very seldom black or white, so too we should carry a healthy scepticism of science in the justice system.

Similarly, as we acknowledge that the legal world is riddled with competitiveness, ego, and close connection between counsel and client, so too we should acknowledge that the scientific world is likewise fraught.

Such scepticism of science, and acknowledgement of the scientific profession, gives rise to possibilities for the astute and knowledgeable litigator to use science and experts as effective tools in order to perhaps, just perhaps, come closer to the truth.

Dr Chris Gallavin is an Associate Professor and Dean of Law at Canterbury University. He has published extensively on criminal justice and on evidence and procedure in particular. He is the author of the appellant handbook, Evidence (LexisNexis, Wellington, 2008), and regularly undertakes consultant work in the area of the law of evidence.

Last updated on the 17th March 2016