As part of its new series of presentations on science communication, the World Health Organization held a webinar earlier this month on communicating risks and evidence during a public health emergency. Speakers associated with the University of Cambridge’s Winton Centre for Risk and Evidence Communication and the Harding Center for Risk Literacy at the University of Potsdam discussed their research on the presentation of scientific information to various audiences.

As the Winton Centre’s Alexandra Freeman explained in her introductory presentation, the first decision science communicators need to make is whether their goal is to inform or to persuade. While both goals are difficult to achieve, it is easier to measure the effectiveness of communications intended to persuade—for example, by verifying a change in audience behavior. The focus of the webinar presentations was on measuring the effectiveness of specific communication tactics intended to inform, a much more difficult task. This post presents four takeaways from the webinar, the recorded version of which is available on YouTube.

1. Presenting only relative risks can leave out important context.

Freeman set the stage by introducing the challenges associated with communicating numbers to the public. To illustrate, she discussed a controversy from 1995, when the U.K. Committee on Safety of Medicines said that the new, third generation of the oral contraceptive pill “doubles” the rate of potentially fatal venal thrombosis. Media seized on the idea that the risk had increased substantially; one high-circulation magazine cover showed a close-up of a woman’s mouth with a white pill on her tongue and the headline “Kiss of Death.” Researchers would later find that the number of abortions in England and Wales was 8 percent higher in 1996 than in 1995, reversing an annual decline that had begun in 1991. A similar trend was identified in the number of conceptions. The increases in abortions and conceptions suggest that significantly fewer people took the contraceptive pill following the committee's communication in 1995, possibly due to concerns based on how risk was portrayed.

While stories about the doubled rate of potentially fatal venal thrombosis were accurate, they left out important context: the likelihood had increased from 1 in 7,000 per year for the second-generation pill to 2 in 7,000 per year for the third-generation pill. In this case, Freeman said, “giving just the relative risk was missing crucial information.” It’s perhaps likely that communications focused on the 2-in-7,000 risk would not have resulted in significant changes in behavior.

2. The format of numbers affects perceptions of risk, and frequencies “feel” riskier than percentages.

Freeman shared a more recent example of how individuals’ perceptions of risk change depending on how numbers are presented. The Winton Centre conducted a survey that presented several statements about the likelihood of death from COVID-19 and asked participants to indicate how “risky” each statement felt. Results showed that people thought a “5 in 100” chance of death felt riskier than a “5 percent” chance, and a “1 in 20” chance felt riskiest of all, even though the risk communicated by each of these statements is exactly the same. Repeating the survey with different risks—12 percent vs. 12 in 100 vs. 1 in 8, and 20 percent vs. 20 in 100 vs. 1 in 5—found the same pattern. As Freeman observed, in science communication, it’s not just what you say—it’s how you say it.

3. “Fact boxes” have potential to increase audience comprehension.

The Harding Center’s Christin Ellermann presented research on the use of “fact boxes,” which are evidenced-based summaries concerning a particular risk that are designed to inform, not to direct behavioral change. Ellermann discussed fact boxes that addressed the safety and effectiveness of mRNA vaccines for COVID-19; several examples are available from the Harding Center website. Fact boxes have several elements:

• a description of the reference class—for example, adults under the age of 60
• relevant endpoints for benefits and harms
• numbers presented as absolute risks
• short summaries of additional relevant information—for example, a note about both typical and rare side effects
• a list of sources for the information presented

According to Ellermann, a survey conducted in Germany found that people who were undecided about COVID-19 vaccination were more likely to get vaccinated after they saw the fact box, even though persuasion was not the goal.

4. The “PROVE” framework can reduce negative responses to science communication.

Last November, authors from the Winton Centre published an article in Nature that presented five rules for communicating scientific evidence. Their colleague, John Kerr, formalized those rules as the “PROVE” framework. As Kerr explained during the WHO webinar, the elements of PROVE are:

• pre-bunk—that is, preempt misinformation and misunderstandings
• reliably inform
• offer balance
• verify quality
• explain uncertainty

To test the effectiveness of the PROVE framework, a team from the Winton Centre presented two versions of information about COVID-19 vaccines to around 2,000 individuals in the U.K. who were unvaccinated. One version was verbatim from the website of the U.K. National Health Service, which Kerr described as relatively pro-vaccine; the other version was the same information rewritten according to PROVE guidelines. For example, the following sentences from NHS…

The COVID-19 vaccine is safe and effective. It gives you the best protection against COVID 19.

…were rewritten as:

The COVID-19 vaccine is now being offered in the U.K. This information is designed to help you make an informed decision about vaccination.

Kerr’s team found that people who already had a positive view of vaccines trusted both versions equally and that neither version affected their beliefs and intentions regarding the vaccine. Respondents who were skeptical of vaccines, however, exhibited more trust in messaging rewritten according to PROVE. They also reported that the PROVE messages elicited less negative reactions than the original versions. The results suggest that “transparent and balanced communication of COVID-19 vaccines doesn’t negatively impact vaccine attitudes and intentions,” Kerr said.

For more information, watch the recorded presentation. Previous SynergistNOW blog posts on science communication include:

• “New Research on Scientific Misinformation”
• “Communicating About Vaccines”
• “Science and Storytelling”
• “Talking about Science: Goodbye—and Good Riddance—to the Deficit Model”