At this critical time in the modern history of the human race, mathematical models have been pushed into the foreground. Epidemic forecasting informs policy and even individual decision-making. Sadly, scientists and journalists have completely failed to communicate how these models work.

Last week the Financial Times published the headline ‘Coronavirus may have infected half of UK population’, reporting on a new mathematical model of COVID-19 epidemic progression. The model produced radically different results when the researchers changed the value of a parameter named ρ – the rate of severe disease amongst the infected. The FT chose to run with an inflammatory headline, assuming an extreme value of ρ that most researchers consider highly implausible.

Since its publication, hundreds of scientists have attacked the work, forcing the original authors to state publicly that they were not trying to make a forecast at all. But the damage had already been done: many other media organisations, such as the BBC, had already broadcast the headline [1].

Epidemiologists are making the same mistakes that the climate science community made a decade ago. A series of crises forced climatologists to learn painful lessons on how (not) to communicate with policy-makers and the public.

In 2010 the 4th IPCC report was attacked for containing a single error – a claim that the Himalayan glaciers would likely have completely melted by 2035 (‘Glacier Gate’). Climate denialists and recalcitrant nations such as Russia and Saudi Arabia seized on this error as a way to discredit the entire 3000 page report, which was otherwise irreproachable.

When the emails of the Climatic Research Unit (CRU) of University of East Anglia were hacked in 2009, doubt arose over the trustworthiness of the entire climate science community. Trust was diminished because the head of the CRU refused to openly share computer code and data. The crisis was to cast a pall over the climate science community for many years.

By the time of the 5th IPPC report, mechanisms had been developed to enforce clear communication about the uncertainty surrounding predictive models; and transparency about models and data. The infectious disease community needs to learn these lessons. And learn them quickly.

Over the last days, several infectious disease non-experts have gained media coverage for various ‘too good to be true’ (and plain wrong) coronavirus forecasts. Ideologically-driven commentators have used these results to justify easing of social distancing rules, with potentially devastating consequences.

Scientists and journalists have a moral responsibility to convey the uncertainty inherent in modelling work. There is much at stake. Here we recommend a handful of rules for policy-makers, journalists and scientists.

Rule 1. Scientists and journalists should express the level of uncertainty associated with a forecast

All mathematical models contain uncertainty. This should be explicit – researchers should communicate their own certainty that a result is true. A range of plausible results should be provided, not just one extreme result.

Rule 2. Journalists must get quotes from other experts before publishing

The worst cases of poor COVID-19 journalism have broken this simple rule. Other scientists have weighed in after publication. But by then a misleading article has reached an audience of millions and taken hold in the public consciousness.

Rule 3. Scientists should clearly describe the critical inputs and assumptions of their models

How sensitive is the model to the input parameters? How sure are you of those parameters? Do other researchers disagree?

Rule 4. Be as transparent as possible

Release data and code so that scientific scrutiny can take place. Consider open peer-review so that other experts can quickly give their opinion on a piece of work.

Rule 5. Policy-makers should use multiple models to inform policy

The Imperial college model created by Neil Ferguson has been reported on almost exclusively as the modelling input to UK pandemic policy. Have other models from other groups been considered? What is the degree of agreement between the models?

Rule 6. Indicate when a model was produced by somebody without a background in infectious diseases

Would we encourage an epidemiologist to apply ‘fresh thinking’ to the design of an electrical substation? Perhaps we should treat with caution the predictions of electrical engineers about pandemic disease outbreaks.

Notes

[1] Post-publication, the FT have modified the report text but have left the headline unchanged.

Thanks to Danielle Belgrave, Piers Stobbs, Lucy Hayes and Adam Davison for helpful comments