Misleading statistics within criminal trials: The Sally Clark case

摘要

Richard Nobles and David Schiff revisit the Sally Clark case and consider the presentation by non-statisticians of statistical evidence in court. In the media reporting which followed the conviction of the solicitor Sally Clark for the murder of two of her infant children, there was frequent recourse to a statistic given in evidence by the eminent paediatrician Professor Meadow that the chances of a second cot death in the same family were 73 million to 1. At that stage, the statistic served to dispel any doubts in readers' minds that a person from Sally Clark's background could have committed such a crime. Later, and most particularly at the time of her two appeals (the second of which was successful), this statistic was again reported, but with the rider that it was a misleading statistic, with the implicit (and often explicit) suggestion that it could have made a major contribution to a miscarriage of justice.