Neil Ferguson clarified his Covid-19 projections. Good for him.

Give Neil Ferguson a break. Nearly two weeks ago Mr. Ferguson, an epidemiologist with Imperial College London, issued a report on Covid-19. Much of the public attention focused on his worst-case projection that there might as many as 2.2 million American and 510,000 British deaths. Fewer paid attention to the caveat that this was “unlikely,” and based on the assumption that nothing was done to control it. The report was one reason that led Prime Minister Boris Johnson to change policy and lock Britain down. Under the Imperial College model, the projection was that the steps Mr. Johnson had been taking would cut the number of projected deaths in half but still leave about a quarter million British dead. Now Mr. Ferguson has clarified his estimates. He told Parliament this week that he now reckons the number of deaths in the U.K. “would be unlikely to exceed 20,000”

There’s a warning here about science and journalism. Surely if we hope to neutralize a pandemic we don’t fully understand, we need to encourage a culture in which scientists feel able to adapt and clarify with new evidence. Scientists would also help themselves if, in explaining their findings, they would be more candid about the assumptions and variables. This goes double for the press.

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