Last month, in advance of a report on 14 hospital trusts with relatively high death rates, it was widely reported that there had been 13,000 “unnecessary” deaths.
But, as a leading academic points out in today’s British Medical Journal, this demonstrates an epic lack of understanding of the concept of an average.
The 13,000 figure is the difference between the actual number of deaths in the 14 hospitals compared to the “expected” level. But what some writers failed to understand is that the “expected” level equated to the national average. As a result much of the coverage was seriously misleading, according to David Spiegelhalter, Winton professor for the public understanding of risk at the University of Cambridge. Read more