In this op-ed, the authors of the letter explain why they are calling on the government to explain the scientific rationale behind their policy decisions thus far.

The letter has been signed by nearly 600 behavioural scientists from around the United Kingdom (at the time of publishing).

The open letter raises questions about the behavioural science evidence that may have been used to justify this decision—though a lack of transparency from the government has made it hard to discern what the official policy is.

Social distancing measures, like closing restaurants and pubs, cancelling school and events, and working from home are being enforced across Europe. The U.K. government, however, has taken a decidedly different approach. At the time of publishing, around 1,400 cases of the virus had been detected in the U.K., up 1,000 from the week before.

We are presently facing the biggest challenge in a generation. The novel coronavirus, or COVID-19, is a global pandemic that is and will continue to test us locally, nationally, and internationally on many levels. In what is a fast-moving situation, policymakers are forced to make high-stakes decisions under enormous pressure. In order to have the best shot at getting things right, those decisions must be informed by science wherever possible.

But it is not just the underlying science that matters: governments will need to be able to move decisively and effectively, and they will require high levels of public trust. In that context, the wider scientific community faces unique challenges with respect to how best to support government actions. There is the ongoing research into COVID-19 that huge numbers of researchers worldwide have immediately become engaged in. But there is also the question of whether scientists should seek to voice opinions directly in the public arena.

The risk of doing so is that it may undercut government credibility and hence undermine public trust, while generating little more than a cacophony of voices of many different opinions. The risk of not doing so is that vital opportunities for scrutiny of the many, complex, interlocking parts involved in the decisions are missed, errors are made, or better alternatives are overlooked. Lives may be lost as a result.

We chose to address the U.K. government with an open letter concerning the decision to delay social distancing measures as a means of slowing the spread, seemingly because starting distancing too soon might lead to “behavioural fatigue”.

In this bind, we chose to address the U.K. government with an open letter concerning the decision to delay social distancing measures as a means of slowing the spread, seemingly because starting distancing too soon might lead to “behavioural fatigue”.

Unfortunately, both the intended meaning of “behavioural fatigue” and its precise role in the U.K.’s science-based approach remain vague because information about it seems only to have been disseminated through media interviews of government sources and officials involved in the policy process (see Bloomberg, March 11, 2020; The Guardian, March 12, 2020; The Guardian, March 13, 2020; and The Guardian, March 13, 2020). What is known seems to be this: if imposed too early, people could grow tired of bans and cease to comply with them, possibly before the actual peak of the pandemic.

At the time of writing, many voices from across science, epidemiology, and public health are urging the adoption of such measures in the U.K.; and many other countries are moving towards “lockdown.” The exponential growth rate of the virus suggests that time is of the essence, and U.K. society seems to be running ahead of government recommendations: Premier League football has been suspended, many higher education institutions are voluntarily suspending face-to face instruction, and prominent employers are shutting offices and shops, recommending working from home where possible, or reducing staff density where offices remain open.

The burden of proof, therefore, lies with the government to explain its reason for delay. But can this burden of proof be met? Is behavioural fatigue a sound reason for delaying social distancing?

While we appreciate that the concept of behavioural fatigue may well be relevant and something to take into consideration when designing public health policies for dealing with COVID-19, we are concerned, as behavioural scientists, about the lack of evidence directly bearing on this issue. To the best of our knowledge, there is no sound evidence base to suggest that behavioural fatigue would undermine early interventions based on social distancing, and especially not in a case like the one we currently face.

The burden of proof, therefore, lies with the government to explain its reason for delay. But can this burden of proof be met? Is behavioural fatigue a sound reason for delaying social distancing?

Nor did our open letter, now signed by hundreds of colleagues, prompt a flood of emails alerting us to a large body of research we had overlooked. What studies we did find, such as studies on the continuation of protective measures during past epidemics such as H1N1, seemed to indicate that yes, compliance with such behaviours tailed off over the course of an epidemic, but it is unclear that there is more at work here than the fundamental, well-established principle that uptake of protective behaviours is moderated by perceived threat (for example, see this review on attitudinal determinants of protective behaviours from the U.K.’s Influenza Pandemic Preparedness guidance documentation).

That wider principle makes the applicability of past studies involving flu pandemics seem problematic, given that what we are dealing with now is very much not “just a flu”, as we are now seeing daily from devastatingly affected cities and regions across the world. The fact that there is now, for the first time ever, a halt to top flight football is a high-visibility indicator that we are dealing with a very different situation from past experience.

Furthermore, the importance of perceived threat implies that a lack of more drastic measures may itself undermine those actions (chiefly hand washing) that citizens are already expected to take. If the government takes no further action, why should I bother washing my hands or refraining from hugging my friends?

Time is of the utmost essence. We currently know too little to ascertain the best plan of action. But global scientific efforts are progressing rapidly in understanding the nature of the virus, how to treat it, and how to contain its spread, not to mention practical preparedness. Immediate social distancing measures may buy us valuable time.

If the argument of behavioural fatigue is really driving U.K. policymakers to delay social distancing, this concept had better stand up to scrutiny. We thus urge the government to provide a clear indication how behavioural fatigue features in the decision-making and modelling, and any behavioural evidence for the phenomenon, so that the evidence and the reasoning from it may be evaluated.

Our letter is not an attempt to undercut policymakers, but aims to help create more robust, rigorous, and better policy at this critical moment.

To reiterate, the policy decision process is a complex whole of many individual parts, spanning multiple disciplines. We should not seek to hijack that process, particularly when we have mastery of only a fraction of the relevant considerations. But we can scrutinize and check those parts that are within our own areas of expertise, and we can scrutinize the overall arguments and considerations about how those parts are supposed to hang together. In fact, that is exactly the kind of activity we have been trained to do.

Our letter is not an attempt to undercut policymakers, but aims to help create more robust, rigorous, and better policy at this critical moment.