Sally Clark, a 34 year old mother, was convicted in 1999 of the murder of her two sons Christopher, who died at the age of 11 weeks in December 1996, and Harry, who died at the age of 8 weeks in January 1998. Both the children had been previously healthy; they died suddenly in her care, in the evening, at home. Postmortem examinations of both children showed multiple abnormal findings.

After the verdict, the media reported the family's claim that both children had “died of cot death” and that incorrect statistical evidence given at the trial had greatly underestimated the likelihood of recurrence of cot death. The BMJ published an editorial as deficient in its sources as it was sensational in its title.1 It was called “Conviction by mathematical error?” and it ignored the fact that at the trial neither the defence nor any of the expert witnesses advanced the claim that the children's deaths were examples of sudden infant death syndrome. The risk of recurrent sudden infant death syndrome was irrelevant to the conviction.