A statistician in today's Guardian on Hahn & 35% https://www.theguardian.com/commentisfree/2020/aug/31/politicians-covid-19-statistics-statisticians
Numbers may not measure what you think they may be measuring, but they are rarely completely wrong. That’s why the statistical community let out a collective gasp last Sunday when Stephen Hahn, the commissioner of the US Food and Drug Administration, told a press conference that treatment with convalescent plasma would mean that of “100 people who were sick with Covid-19, 35 would have been saved”. If true, this would be one of the most remarkable medical discoveries in history, saving one life for every three people treated. But it is completely false. In fact 8.9% of the treated group died, compared with 13.7% of a comparison group, a 35% relative difference. The absolute difference was 5%, so if we believed the figures, in fact 20 people had to be treated to save one life. But we should not even believe those numbers, being based on selected patients receiving the treatment, and not comparing like with like in a proper randomised design.
This is possibly the most statistically dim-witted utterance I have witnessed from any authority during this crisis, and he’s up against some pretty stiff competition, not least from the president flanking him at the press conference.