Statistics Authority criticises Covid-19 testing figures

Norgrove said the current testing figures are “far from complete and comprehensible”, in a letter addressed to the secretary of state for health, Matt Hancock.

In early May, the statistics body requested clarity from the government over the data. Today’s letter responds to correspondence from Hancock on 27^th May, in which he outlined the changes made by government to how testing information is published.

However, Norgrove said the testing statistics still “fall well short” of the expectations of the Code of Practice for Statistics. He wrote: “It is not surprising that given their inadequacy data on testing are so widely criticised and often mistrusted.”

The headline total of tests currently adds together tests that have been carried out with those that have been posted out, which Norgrove described as “misleading”. There is no data about how many tests that have been posted out and then successfully completed, and the government’s daily press conference slides do not include the date when tests were carried out, he noted. 

The statistician also criticised the way in which testing figures are presented, saying that it is “difficult to understand” and “makes little sense” unless referring to the technical notes.

The government should take a systematic approach to the key metrics used to measure the success of its test and trace programme to avoid similar issues arising, added Norgrove.

He said: “The statistics will need to be capable of being related to the wider testing data and readily understood by the public, through for example population adjusted maps of hotspots.”