Setting the agenda in research Comment MATTHEW HORWOOD/GETTY MATTHEW Consider what information — in what format — would best support your audiences’ decisions. Five rules for evidence communication Michael Blastland, Alexandra L. J. Freeman, Sander van der Linden, Theresa M. Marteau & David Spiegelhalter Avoid unwarranted certainty, e persuasive”, “be engaging”, There are myriad examples from the cur- “tell stories with your science”. rent pandemic of which we might ask: have neat narratives and partisan Most researchers have experts always been explicit in acknowledging presentation; strive to heard such exhortations many unknowns? Complexity? Conflicts of interest? inform, not persuade. times, and for good reason. Inconvenient data? And, importantly, their “BSuch rhetorical devices often help to land the own values? Rather than re-examine those message, whether that message is designed cases, we offer ideas to encourage reflection, to sell a product or win a grant. These are the based on our own research. traditional techniques of communications Our small, interdisciplinary group at applied to science. the University of Cambridge, UK, collects This approach often works, but it comes empirical data on issues such as how to com- with danger. municate uncertainty, how audiences decide 362 | Nature | Vol 587 | 19 November 2020 ©2020 Spri nger Nature Li mited. All ri ghts reserved. ©2020 Spri nger Nature Li mited. All ri ghts reserved. what evidence to trust, and how narratives be To Inform and Not Persuade.” The media affect people’s decision-making. Our aim is might urge us to aim for memorable sound to design communications that do not lead bites or go beyond the strength of the data: people to a particular decision, but help them be honest and aware of such traps. Quick tips for to understand what is known about a topic and to make up their own minds on the basis Offer balance, not false balance sharing evidence of that evidence. In our view, it is important to We can’t inform people fully if we don’t convey be clear about motivations, present data fully the balance of relevant evidence. The aim is to ‘inform but not persuade’, and and clearly, and share sources. We are all subject to a suite of psychological — as the philosopher of trust Onora O’Neill We recognize that the world is in an biases that mean we sometimes apply evidence says — “to be accessible, comprehensible, ‘infodemic’, with false information spread- to shore up our own beliefs, and find it difficult usable and assessable”. ing virally on social media. Therefore, many to accept evidence that goes against our ideas scientists feel they are in an arms race of and hypotheses. People also like to tell (and • Address all the questions and concerns of communication techniques. But consider the hear) stories that don’t meander through the target audience. replication crisis, which has been blamed in thickets of opposing opinions or pros and cons. • Anticipate misunderstandings; part on researchers being incentivized to sell But evidence communicators must challenge pre-emptively debunk or explain them. their work and focus on a story rather than on these instincts and offer evidence in the round. • Don’t cherry-pick findings. full and neutral reporting of what they have Partial presentation of evidence crops up • Present potential benefits and possible done. We worry that the urge to persuade or across scientific literature and in the public harms in the same way so that they can be to tell a simple story can damage credibility domain. Often, the argument made is that compared fairly. and trustworthiness. people can’t take in lots of information at once. • Avoid the biases inherent in any Instead, we propose another approach. We If you’re presenting written information, you presentation format (for example, use both call it evidence communication. can make it easier for them. Here’s a simple ‘positive’ and ‘negative’ framing together). tip from research in medical communication: • Use numbers alone, or both words and Inform, not persuade display the pros and cons in a table rather than numbers. Conventional communication techniques stating them in the text. Imagine a table com- • Demonstrate ‘unapologetic uncertainty’: might ‘work’ when the aim is to change paring proposed transmission-prevention be open about a range of possible people’s beliefs or behaviours. But should policies that lays out the projected harms and outcomes. that always be our aim? benefits of each policy in terms of mortality, • When you don’t know, say so; say what Early in the pandemic, we surveyed people morbidity, economics, environment and you are going to do to find out, and by across 13 countries from South Korea to mental health, breaking down subgroups and when. Mexico and asked what sources of information timescales. For your audiences, knowing what • Highlight the quality and relevance of the they trusted. We also asked them why. Their the key pros and cons are is crucial. underlying evidence (for example, describe answers show how sensitive people are to the We neglect people's interests at our peril. the data set). aims and interests of communicators. As soon as we are perceived to be ignoring or • Use a carefully designed layout in a clear “They sell news, not truth,” said one UK underplaying something our audience consid- order, and include sources. respondent about journalists; “I believe the ers important, our motivations — and hence Government are being guided by scientists our trustworthiness — will be questioned. spongiform encephalopathy. He adopted the and genuinely care about the population,” As one of the Australian participants in our following strategy: say what you know; what you said another; “WHO is paid by China,” replied COVID-19 survey in March said about their don’t know; what you are doing to find out; what a respondent from Japan. Friends and family reason for distrust of official information: “Are people can do in the meantime to be on the safe were often warmly described as having “no they hiding the full effects from us?” side; and that advice will change3. We check any- reason to lie”. one talking to the public about COVID-19 against These observations fit with the literature, Disclose uncertainties this list, especially the second point. which identifies expertise, honesty and good Part of telling the whole story is talking about New Zealand’s response to the pandemic intentions as the key to trustworthiness1. what we don’t know. has been praised. And the country’s Ministry Researchers need to demonstrate all three: The simplest argument for stating of Health web page on COVID-19 test results we cannot expect to be trusted on the basis uncertainty is that what we think we know is includes several paragraphs describing uncer- of expertise alone. constantly changing (wearing face coverings tainties, including the likelihood of a false neg- So how do we demonstrate good is an example). One of us (M.B.), writing with ative (meaning that a test says someone’s not intentions? We have to be open about our others in the medical journal BMJ, admitted infected when they actually are). The US Centers motivations, conflicts and limitations. that at some point, all three authors had been for Disease Control and Prevention page men- Scientists whose objectives are perceived wrong about COVID-19 (ref. 2). So, either we tions no such uncertainties. Neither does the as prioritizing persuasion risk losing trust. had better be certain, and right — or we should UK National Health Service website (despite During the COVID-19 crisis, one of us (D.S.) more humbly state our uncertainties. us raising the issue with them): it was deemed has frequently had to refuse journalists who When zoologist John Krebs became chair of too confusing. Even with a highly accurate test, tried to draw him away from his intention to the UK Food Standards Agency in the 2000s, thousands of people get false negatives and false stick to statistical evidence. As he told The he faced a deluge of crises, including dioxins assurance that could lead to risky behaviours. Times, “The banner across my T-shirt should in milk and the infectious cattle disease bovine When we trialled the wording with and Nature | Vol 587 | 19 November 2020 | 363 ©2020 Spri nger Nature Li mited. All ri ghts reserved. ©2020 Spri nger Nature Li mited. All ri ghts reserved. Comment without the explicit uncertainties around the attempts to sow doubt (known as prebunking), repeating: researchers should not take up test result, we found that the uncertainties they resist being swayed by misinformation or the reins of rhetoric blindly or feel that they did not seem to undermine trustworthiness. disinformation6–8. should always harness the tools used by the However, the wordings did affect people’s per- Prebunking requires anticipating potential media and entertainment industries to shape ception of whether the test recipient should misunderstandings or disinformation attacks, people’s emotions and beliefs. Nor should they isolate if they got a negative result. In other and that means understanding the concerns of assume that they are apolitical, unbiased and words, people correctly interpreted the mes- the audience. Read public forums and popular utterly objective — all of us have values, beliefs sages without having their trust undermined news sources. Consider what decisions your and temptations. Even if we choose to be an by an upfront description of uncertainties. audiences are making and what informa- ‘honest broker’, the first person we need to be Other research finds little downside in tion — in what format — would best support honest with is ourselves. expressing findings as a range (such as these, from whether to wear a face covering to In our research across ten countries, we ‘between x and y’) rather than an exact num- see how people’s willingness to be vaccinated ber4.