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Allan Reese has written about the case of the woman convicted of killing her two children, apparently partly on the basis of a statistical argument. I thought members might be interested in some data. In 1996, the most recent year for which data are available, there were 649,489 live births in E&W. There were 4,959 deaths in the first year of life, including 394 sudden infant deaths (SIDS or cot deaths) and 14 homicides. Thus the probability of a cot death is 1 in 649489/394 = 1,648. If deaths were independent, which they are not because there are familial risk factors, the risk that a fimily of two babies would have two cot deaths would be 1 in 1,648*1,648 = 2,715,904. Presumably some other adjustment was applied for social factors as the figure given in the press is said to apply to `well-to-do families'. But the same calculation for homicide gives a risk that that two baies will both be murdered as one in (649489/14)^2 = 2,152,224,291. If the first figure is relevant, so is the second. As Allan says, neither is relevant. Martin . Prof J M Bland Dept of Public Health Sciences St George's Hospital Medical School London SW17 0RE, UK Tel 0181-725 5492 email [log in to unmask] ----------------------------------------------------------------- This mail sent through SGHMS Webmail: https://webmail.sghms.ac.uk/ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%