User:ErrantX/Sandbox/Cot death trials controversy

The Cot death trials controversy relates to a series of British trials of mothers accused of killing their children. British paediatrician Sir Samuel Roy Meadow theorised that cases previously ascribed as Sudden infant death syndrome were in fact examples of child abuse, due to mothers suffering from Münchausen syndrome by proxy.

Meadow testified as an expert witness at a number of "cot death" trials leading to several high profile convictions. In 2003 questions about the validity of his theory and the statistical evidence led to some of the convictions being overturned and further appeals being launched in other cases.

The controversy lead to a 2004 change in the law to preclude people from being convicted solely on the grounds of expert testimony.

Münchausen syndrome by proxy
Münchausen syndrome by proxy describes a pattern of behaviour where a care giver deliberately induces medical problems in others with the aim of satisfying a need for attention. The condition was first described in the late 1970s first by Money and Werlwas (1976) and later developed by Meadow. After initial scepticism the medical community the theory has been widely adopted.

Meadow continued to develop and research the theory, coming to believe that many apparent cot deaths were the result of physical abuse, particularly in cases where multiple cot deaths had occurred. In XXXX he said; "There is no evidence that cot deaths runs in families but there is plenty of evidence that child abuse does". His views, altough not entirely developed by himself, came collectively to be known as "Meadow's law".

In court, as an expert witness, Meadow stated that "one sudden infant death in a family is a tragedy, two is suspicious and three is murder unless proven otherwise" (Meadow's law). He claimed that, for an affluent non-smoking family, the probability of a single cot death was 1 in 8,543, so the probability of two cot deaths in the same family was around "1 in 73 million" (8543 × 8543). Given that there are around 700,000 live births in Britain each year, Meadow argued that a double cot death would be expected to occur once every hundred years.

Expert testimony
Meadow rose to public prominence in 1993, when he brought expert testimony in the trial of Beverley Allitt, a paediatric nurse accused of murdering several of her patients. Allitt was found guilty and sentenced to life imprisonment, which many saw as vindication of Meadow's theories.

Over the following years Meadow continued to testify in many other trials, many of which concerned cases previously diagnosed as cot death or sudden infant death syndrome (SIDS).

Sally Clark
Meadow's testimony came under scrutiny after the conviction of Sally Clark (August 1964 – 15 March 2007) for the murder of her two children in 1999. Whilst giving evidence at her trial Meadow gave statistical evidence over the likelihood of two cot deaths occurring in the same family; saying that the odds were 73,000,000:1. This figure was criticised during the trial, and subsequent appeal, as being inaccurately obtained.

In October 2001, the Royal Statistical Society (RSS) issued a public statement expressing its concern at the "misuse of statistics in the courts". It noted that there was "no statistical basis" for the "1 in 73 million" figure Meadows had quoted. In January 2002, the RSS wrote to the Lord Chancellor pointing out that "the calculation leading to 1 in 73 million is invalid".

Meadow's calculation was based on the assumption that two SIDS deaths in the same family are independent of each other. The RSS argued that "there are very strong reasons for supposing that the assumption is false. There may well be unknown genetic or environmental factors that predispose families to SIDS, so that a second case within the family becomes much more likely than would be a case in another, apparently similar, family." The prosecution did not provide any evidence to support its different assumption. In a 2004 article in Pediatric and Perinatal Epidemiology, Professor of Mathematics Ray Hill of Salford University concluded, using extensive SIDS statistics for England, that "after a first cot death the chances of a second become greatly increased", by a dependency factor of between 5 and 10.

It is likely that the court committed a statistical error known as the "prosecutor's fallacy". Many press reports of the trial reported that the "1 in 73 million" figure was the probability that Clark was innocent. However, even if the "1 in 73 million" figure were valid, this should not have been interpreted as the probability of Clark's innocence. In order to calculate the probability of Clark's innocence, the jury needed to weigh up the relative likelihood of the two competing explanations for the children's deaths. Although double SIDS is very rare, double infant murder is likely to be rarer still, so the probability of Clark's innocence was quite high. Hill calculated the odds ratio for double SIDS to double homicide at between 4.5:1 and 9:1.

Hill raises a third objection to the "1 in 73 million" figure: the probability of a child dying from SIDS is 1 in 1,300, not 1 in 8,500. Meadow arrived at the 1 in 8,500 figure by taking into account three key characteristics possessed by the Clark family, all of which make SIDS less likely. However, Meadow "conveniently ignored factors such as both the Clark babies being boys – which make cot death more likely". Hill also argues:

"When a cot death mother is accused of murder, the prosecution sometimes employs a tactic such as the following. If the parents are affluent, in a stable relationship and non-smoking, the prosecution will claim that the chances of the death being natural are greatly reduced, and by implication that the chances of the death being homicide are greatly increased. But this implication is totally false, because the very same factors which make a family low risk for cot death also make it low risk for murder."

During the second appeal, the court noted that Meadow's calculations were subject to a number of qualifications, but "none of these qualifications were referred to by Professor Meadow in his evidence to the jury and thus it was the headline figures of 1 in 73 million that would be uppermost in the jury's minds". The appeal court concluded that "the evidence should never have been before the jury in the way that it was when they considered their verdicts". The judges continued, "we rather suspect that with the graphic reference by Professor Meadow to the chances of backing long odds winners of the Grand National year after year it may have had a major effect on [the jury's] thinking notwithstanding the efforts of the trial judge to down play it".

2003 trial and appeals
Following Clark's successful second appeal, in January 2003, the Attorney General ordered a review of 100 similar cases. Following her release Clark never recovered from the ordeal, suffering from psychological problems and alcohol dependency until her death from alcohol poisoning in 2007.

In June 2003 Meadow gave evidence at the trial of Trupti Patel, a pharmacist accused of killing three of her children. By this time some of Meadow's theories about multiple cot deaths had been discredited, and Patel was eventually acquitted.

A third related court case occurred in December of the same year. Angela Cannings had been convicted in XXXX on the basis of Meadows evidence, in her 2003 appeal the conviction was quashed.

Aftermath
In 2004...