He claimed that, for an affluent non-smoking family like the Clarks, the probability of a single cot death was 1 in 8,543, so the probability of two 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. 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. In January 2002, the RSS wrote to the Lord Chancellor pointing out that "the calculation leading to 1 in 73 million is false". Meadow's calculation was based on the assumption that two SIDS deaths in the same family are independent. 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 Paediatric 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. The ruling was also subject to 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. In other words, murder was not the only alternative explanation for the deaths in the way that one might have inferred from asserted probability of double SIDS. 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