Models behind coronavirus plans mostly ‘educated guesses’

“…..a half-good answer given before the decision is made is infinitely more useful than a perfect answer given after the decision is made.”

[Don’t treat the models with reverence – they are only the tools of the trade.]

Rhys Blakely, Science Correspondent www.thetimes.co.uk

The mathematical models underpinning the government’s Covid-19 strategy are largely informed by “educated guesswork, intuition and experience”, one of its scientific advisers has said.

Graham Medley, who sits on the scientific advisory group for emergencies (Sage), made the remarks on Monday during an online lecture organised by the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge.

“At the moment, we’re having to do it by making educated guesswork, and intuition and experience, rather than being able to do it in some kind of semi-formal way,” Professor Medley told his audience. “But a half-good answer given before the decision is made is infinitely more useful than a perfect answer given after the decision is made.”

He also chairs the Spi-M sub-committee, which focuses on modelling and feeds into Sage. He said that it lacked good information on how Covid-19 might be spread in shops, pubs, gyms and hairdressers. “If we want to get an idea of when, for example, in the United Kingdom we’re going to be able to open pubs, we’re going to have to understand how people might use them.”

He included a cartoon taken from Private Eye, the satirical magazine, as part of his lecture. It depicted a scientist standing beside a graph marked “Covid cases”. The caption read: “We have, according to the revised projection of the adjusted figures, something more or less approaching no idea.”

Professor Medley said that it was estimated that 10 per cent of the population had been exposed to the virus so far, meaning that the UK was still at the early stage of the epidemic. One main concern was how to gather data on how small, localised outbreaks were likely to flare up as measures were relaxed.

“We are, of course, worried very much about data,” he said. “Where are we going to get the data from? What is it that we should be measuring?”

He added that Spi-M, which had focused on the dangers of an influenza pandemic, had not considered the possibility of offices, shops and restaurants being shut down, presuming that a lockdown would be limited to schools.

Professor Medley also said that a “policy science gap” meant that as scientists tried to convey their findings to ministers and civil servants they were being met with “blank faces”.