On Covid, we need to be careful when we talk about numbers

A recent wave of mistakes shows how misinterpreting data risks misrepresenting the impact of the virus

Since we have just had Maths Week in England, it seems appropriate to look at a wave of recent errors when communicating numbers.

First, the statistics may be described wrongly. The chief executive of NHS England recently claimed: We have had 14 times the number of people in hospital with Covid than we saw this time last year", a claim repeated on Sky News and ITV. But there were fewer Covid-19 patients in England on 4 November (7,201) than a year earlier (11,037). The intended reference was to last August, when there were about 23,000 admissions within two weeks after a positive test, about 14 times higher than last year.