Sally Clark

Sally Clark 1964-2007

Sally Clark
August 9th 2002 New Law Journal vol 152 No 7044
Editorial by Dr. B. Mahendra.

Convicted by flawed science

"How can you be sure she is not the killer of those children?"

"We cannot ever be sure she did or did not do the deed. But what we have are rules by which, to secure a guilty verdict , the Crown has to prove its case beyond all reasonable doubt."

One develops a practised ease in remarking thus when a case has attained the status of a cause celebre as has now the case of Mrs Sally Clark. She, a solicitor, had been convicted in November 1999 of the murder of her two infant children. It soon became clear that it was going to be one of those cases where lingering doubt is raised and left in the minds of observers. In Mrs Clark's case the doubts concerning the scientific evidence given at trial-- both statistical and pathological-- were cast soon after conviction (see New Law Journal, 4 February 2000 p 125) and ever since, in an almost relentless march of news, these doubts have gained in such strength that now more than a whiff of injustice hangs in the air.

An expert for the Crown, Professor Sir Roy Meadow, set down a figure of one in 73 million for a double death to have occurred in the circumstances of Mrs Clark's family through natural causes; a happening translated to lay minds as occurring once every 100 years. This figure has been challenged virtually from the time Professor Meadow, a paediatrician and not a statistician, uttered it in court. It has now been conceded, in the scientific community at least, as likely to have misled the jury. In a recent statement the Royal Statistical Society (RSS) drew pointed attention to the misuse of statistics in the courts in general and in the Sally Clark case in particular. It stated that Professor Meadow's view was ' statistically invalid (and) has no statistical basis.' This is because the figure assumes that 'normal' cot deaths arise independently in families. Not only is there no empirical basis for this assumption but, as the RSS points out, there are very strong a priori reasons for assuming that there are unknown genetic or environmental factors that predispose families to ' cot deaths'. In fact, the empirical evidence points in the opposite direction. A recent study at Manchester University had reportedly discovered a genetic basis to 'cot deaths', associated with a three- fold increase in the risk of 'cot death' in those possessing it compared with the normal population. This may mean that 'cot deaths', like many disease conditions, have a propensity to run in families. As the RSS states, the true frequency of families with two cases of 'cot deaths' may be 'very much less incriminating than the figure presented to the jury at the Clark) trial.' It went onto say this case 'is one example of medical expert witness making a serious statistical error, one which may have had a profound effect on the outcome of the case.' Aggrieved by the statistically semi-numerate usurping of the role of experts, the RSS goes onto demand that only 'appropriately qualified' statistical experts be allowed to give this kind of evidence.

The other strand of tainted evidence involved the testimony of the Crown's expert pathologists, Dr Alan Williams and Professor Michael Green. They had opined that the deaths of the children were due to their being smothered, having initially suggested shaking as the cause of death. The retraction and revision of opinion concerning the cause of death came in the face of a challenge by a defence pathologist. There were numerous other flaws identified in the Crown's pathological evidence and, though attempts were made to counter them, the evidence was seemingly sufficient to be deemed beyond reasonable doubt by the jury and, later, passed muster with the Court of Appeal which held the medical evidence incriminating Mrs Clark to be 'overwhelming'.

There the matter might have rested for these doubts could be plausibly explained as being due to genuine divergences in medical opinion that need not detain a court. Indeed, only a few months ago, Mrs Clark's husband Stephen, dedicated to clearing his wife's name, sounded notably despondent. Then, fortune, which seemed to have deserted the Clarks, skulked back to their side for with the assistance of Mr Martin Bell, the journalist and former independent MP for Tatton, they succeeded recently in persuading the General Medical Council to investigate the evidence given in the case by the two pathologists.

At one level these matters can be seen as a classic illustration of the clash of cultures involving science and the law. Science operates in a world of the provisional and the tentative; the law demands the closures of certainty. If these medical experts had submitted their interpretations and opinions to a learned journal, their errors would have been pointed out to them by their peers with a view to revision, a process that could take months and years. Such luxuries of editorial amendment are not open to a court; stark choices have to be laid before lay judge and jury. Result-- possible injustice (see N.L.J., 16 November 2001 p 1686).

On the other hand it seems odd-- and disturbing-- that the correction of possible injustice should wait upon the serendipities of scientific discovery and the caprices of investigations into professional competence by a regulatory body. But, be that as it may, let us be thankful for slender mercies. There now has arrived through diverse channels information which suggests even greater doubt about the Crown's case against Mrs Clark. Quite simply there exists reasonable doubt regarding the safety of the verdict pronounced in that case. The least the Criminal Cases Review Commission could do is to refer this case back to the Court of Appeal.

Copyright (c). Reproduced by kind permission of New Law Journal and B. Mahendra.

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