Numbers have never really been my thing. However, a few years ago I knew I needed to learn more. Having joined an NHS research ethics committee, I wanted to understand more about health statistics. Fortunately I had the opportunity to complete a postgraduate course in health research – which included a module on statistics. Despite my misgivings about data this turned out to be one of the most enjoyable parts of the course, shedding light on the use and abuse of figures to further an argument.

“Most people use statistics as a drunk … uses lamp-posts for support rather than illumination”

Attributes to Andre Lang

Now, in the light of the pandemic, the world is trading statistics like never before. Government scientists present graphs and tables each week, sometimes daily, to explain the R number (transmissibility); exponential growth; and much, much, more. Even where it might seem that there should be greatest clarity, for example the number of people who have died, there are typically three figures offered. The nuances of criteria and methods reveal just how much the nature of the question influences the form of the answer.

Dorothy Bishop’s bishopblog is one of many sites on the internet that have interrogated the presentation of data and called for greater clarity. Using the example of the difference between relative risk and absolute risk the case is made for the importance of accuracy when communicating data to the public. What might seem to be a huge increase in risk (e.g. 30%) may make limited difference in actual cases depending on the total numbers involved.

“we might hope that, in a pandemic, where public understanding of risk is so crucial, particular care would be taken to be realistic without being alarmist”.

Dorothy Bishop, bishopblog, accessed on 27 January 2021

When I was a curate on placement in a rural church near Lancaster I took part in a service in which the Bishop confirmed 25% of the population of the parish. This meant about 15 people, and it was a fairly rare event for the bishop to come to confirm – so several years’ worth of candidates were gathered up together. It seems astounding that in England in the 1990s a quarter of a parish’s entire population was making a declaration of faith all at once – context is everything.

There appear to be more opportunities for people unaccustomed to interpreting statistical data to find accessible information. Radio 4’s More or Less is a good example of how academic expertise can engage with the questions people are keen to interrogate. In response to the emergence of ‘alternative facts’ there has also been growth in the independent reality checking for which there is an increasing demand. Nowhere could this be more important than in the need for accurate information about the vaccines being offered to combat COVID-19.

It seems to me that one of the problems faced by the desire for both clarity and accuracy is that the truth isn’t always simple. What is the difference between something being ‘safe’ and ‘completely safe’? When vaccines have been developed so quickly there are understandable questions about both immediate side-effects and longer-term consequences. Even a very good sample of people used in the testing phase of the vaccine development cannot be representative of every human characteristic. The question for me is not about the absolute safety of vaccines to be used on billions of people, but about their likely safety and the common good.

Born in a vicarage in the mid-1700s, Edward Jenner is usually seen as the founding figure in the development of modern immunology. At a young age he was given the maxim of William Harvey: “Don’t think; try”. We must be thoughtful, enquiring and considered in our choices – but there comes a time to act. It may be possible to wait for the complete clarity we desire, all the data weighed and balanced, but sometimes we need to make a judgement-call before we know as much as we would like. If the pandemic has taught us one thing, it is that if you wait until something is blindingly obvious you have left it too late. There is a stage in every pandemic when the damage being done is stealthy and silent – yet the foundations of tragedy are being laid comprehensively and irretrievably.

Perhaps one of the legacies of COVID-19 will be to create better systems of public education about risk and probability. Not that any of us will know everything, but – importantly – that each of us might be better able to ask the right questions. Numbers cannot tell us how to live. They provide illumination enabling us to see more clearly the context in which our choices are made. Used well, they support the priorities we have chosen based on our values and moral commitments.