“Communicate” is one of the key components of the risk management process (the others are: set context, identify, assess, measure, treat, and monitor), but it is often the case that little thought goes into how to communicate risk and uncertainty.
At a very simple level, RAG ratings (red-amber-green) are not much use to the 15% of males in the UK who are colour-blind. Also using red to signify something bad would not work well in a Chinese environment.
The State of Florida used to issue hurricane warnings showing a line indicating the most likely path of the hurricane, surrounded by a “Cone of Uncertainty” where there was also a two-thirds chance of the hurricane hitting. Many people living in the Cone did not appreciate the risk and stayed put, only to be hit with the full force of the storm. (Note: “the Cone of Uncertainty” is a somewhat different concept when used in project management).
One way of illustrating long-term life-style risks is to use the concept of the “microlife”. If you take a 26 year-old woman, she is likely to have 57 years of life left which equates to a million half-hours. One microlife is the reduction in life expectancy of 30 minutes and it may result from smoking two cigarettes or drinking three pints of beer. It is not saying that this will definitely happen, but it is an average outcome. A CT scan, which may be medically very necessary, accounts for 180 microlives or a four-day reduction in life expectancy, equivalent to smoking 360 cigarettes. It is a way of measuring risk, but whether or not it is effective in communicating risk, and changing behaviours, is uncertain.
It appears that we respond to risk information at both an emotional and a rational level, and it is important to have both elements for it to be meaningful. One of the emotional considerations is said to be trust in the messenger.
Uruguay has had the lowest number of C-19 deaths per capita in South America despite a higher share of people over 65 than other countries on the continent. The government closed its borders, its schools, cinemas and shopping malls but there was no lock-down. Its policy was called libertad responsable (responsible liberty) and it expected people to act responsibly to thwart the pandemic. Surveys have concluded that this policy has worked as a result of people’s “confidence that the state looks after you”, i.e. the risk was understood and behaviours changed because it was communicated by a trusted source.
Meanwhile in some other countries, in South America and elsewhere, communication has been confusing and contradictory, and it has been delivered by messengers about whom people were less convinced that they were looking after the best interests of everyone. The result of that seems to have been that measures have been much less effective in combating the virus.
Data Sources: 2011 Cambridge University Madingley Lecture by David Spiegelhalter: Communicating Risk and Uncertainty (youtube.com); Wikipedia; The Economist magazine.