Communicating risks: the problem of putting numbers into context

Communicating a risk is far more than ‘getting a number across’ – it’s communicating likelihood and impact in such a way as to allow each member of the audience to make decisions based on their understanding of that risk. This means helping put that likelihood and impact into an appropriate context, and helping the audience weigh up in their mind the costs and benefits of different actions. In this presentation we will illustrate some of our work on communicating personalised risks from Covid-19 and Covid vaccinations, and how these findings might apply to the communication of seismic hazard and risk. For example, is it appropriate to compare the likelihood of someone dying from Covid-19 (if they catch it) with the likelihood of that same person dying from another cause? Our research suggests that people don’t find this as helpful as comparing their likelihood of dying from Covid-19 against the likelihoods of other people with different, familiar risk factors (such as older people, younger people, people with a pre-existing health condition etc). Does the same apply for seismic hazard and risk, such as operational earthquake forecasts? Would it help people to show the chances of their local area experiencing a seismic event compared to the chances in a range of other cities that they know (with high and low hazards)?  We will discuss the pros and cons of such an approach in communicating operational earthquake forecasts.