26 June 2020 | Vital Statistics

It’s claimed that there are three kinds of falsehoods: lies, damned lies and statistics (Charles Dilke 1843–1911). That’s a bit hard on statisticians, but it is true that people often need help in properly interpreting statistics. For instance, Poole Harbour is the largest natural harbour in the world and its average depth is just 48cm (19in). If you didn’t understand statistics, you might try to walk across the harbour… but you would need to be a good swimmer!

Some decades ago, when I read Theology & Sociology at University we were expected to take a course in statistics. There were six of us studying for the joint degree that year and, embarrassingly, I have to confess that 100% of us failed the exam, first time around. Thankfully, after some good remedial teaching we all managed to pass the resit! Since then, I'm pleased to report, I have come to appreciate the value of statistics and have a much better understanding of the underlying maths.

During the last three months we have got used to seeing graphs, summarising various kinds of statistics, at the start of the daily televised government coronavirus briefing. In a sense, we have all become ‘armchair epidemiologists’, scouring the statistics for hopeful trends. It was well before lockdown that, thanks to BBC News web-content, I began to notice some alarming statistics about the mortality rate of the virus. As early as the end of January, The Lancet medical journal had published an article warning that the Wuhan outbreak could become a lethal pandemic. Later, in the pre-lockdown period, when people were generally quite blasé and thinking that for most individuals it would be like catching a case of mild flu, I was much more cautious, thanks to the statistics.

Hindsight is a wonderful thing, as they say. But there is a growing school of thought that lockdown was imposed a fortnight too late in the UK because the scientific consensus had overlooked or misinterpreted the available UK data about the virus in mid-March. The claim was that we were four weeks behind Italy. In fact, we now know that we were just two weeks behind. Instead of infections doubling every five to six days, they were actually doubling every three days. Statistically, that makes a big difference – if an infection doubles every six days, in a month it will spread to 32 people; but, if an infection doubles every three days, it will spread to 1024 people in a month. We might have saved tens of thousands of lives and had a shorter lockdown, if we had interpreted the statistics correctly and locked down earlier. This is not to attribute blame, just to show how important it is to understand statistics!

There’s a statistic that I’ve used once or twice as an illustration in all-age worship: Imagine you told just two people about the Christian gospel, and they went on to tell just two new people each, and the same happened with those two people, and that spread carried on for just over a month. How many people would know about the gospel by then? The answer is surprising – you would reach over 1 billion people within a month and within 3 more days you would exceed the world population! In other words, it is 2 to the power 33. That would be an example of very beneficial contagion!

As the name implies, the Book of Numbers in the Bible has to do with statistics. At the beginning, God tells Moses to conduct a census of the Israelites, clan by clan, counting all males from the age of twenty able to undertake military service. You can see the overall figures in the first chapter of Numbers. Doubtless the census was conducted carefully, but, as with all statistics, there’s reason to be cautious about these figures which seem improbably high. Either some exaggeration has crept in or, more likely, biblical commentators have suggested that there has been mistranslation of one of the Hebrew words, which, instead of meaning ‘thousand’, can also mean ‘contingent’.

One of our greatest statisticians was also keenly interested in military statistics. She was Florence Nightingale and we’ve just celebrated the bicentenary of her birth. Better known as ‘the lady with the lamp’ and as a pioneer of modern nursing during the Crimean War, Florence Nightingale was also particularly skilful in her use of statistics to argue her case for health reforms. Motivated by her strong Christian faith, she went out to the Crimea to nurse British casualties. The conditions she found in the military hospitals profoundly shocked her and led her to submit a damning report, with the help of telling statistics, to the British authorities. She discovered, for instance, that, in the first 7 months of the Crimean campaign, the mortality rate in the military hospitals, from preventable disease alone, was 60% - which was greater than the mortality rate in London during the Great Plague! Poor sanitary practices were killing more soldiers than the enemy. 

Crimean War: Florence Nightingale going around the wards at Scutari Hospital. Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)

It was Florence Nightingale’s love of statistics that ultimately helped to bring about much-needed health reforms. As E W Kopf put it: ‘Her ardent, genuine sympathy for the sick and distressed was greatly augmented by a positive genius for marshalling definite knowledge of the forces which make for disease and suffering’ (‘Florence Nightingale as Statistician’, ASA, Dec 1916, p.404). She is reputed to have said: ‘to understand God's thoughts we must study statistics, for these are the measure of his purpose’. Maybe we should, in future, call Florence Nightingale ‘the lady with the lamp… and the data’!

Philip