The Tiger That Isn’t: Seeing Through a World of Numbers
by Michael Blastland and Andrew DilnotReviewed by Michael HuttonOur lives are more and more dominated by an endless flood of numbers: the average cost of this, the increased risk of that, the number of people who have stopped, or started, doing something else. Yet this increase in data rarely seems to go hand in hand with an increase in understanding and it just seems so difficult to make sense of all the numbers. Does tagging reduce re-offending rates? Should men stop eating cured meats or women stick to one glass of wine a day? What, if any, is the long-term effect of speed cameras on accident rates?
The answers to questions like these are important if we are to make sensible private or public decisions. Michael Blastland and Andrew Dilnot, the creator and presenter respectively of that excellent Radio 4 programme, More or Less, have done something quite unusual: they have written a book about numbers that is lively, readable and entirely practical.
They begin with the assurance that we all know more than we think we do when it comes to making sense of numbers, simply as a result of our own experience. We don’t need to retreat into the “Lies, damned lies and statistics” position, nor see numbers as the deciding factor in any argument. A reasonably sceptical attitude and the habit of asking a few simple questions will usually lead us to the ‘take away’ message buried (often deliberately) in a set of figures. This is certainly not a text book but a book for the consumer of statistics, which is all of us. It is divided into a dozen clearly defined chapters, each dealing with a single topic such as chance, averages, targets, risk, comparisons and correlation, and illustrated with neat everyday examples and reminders of why we should approach even an apparently simple thing like an average with caution. Just remember that an average rainbow would be pure white and most people have more than the average number of feet – which makes them typical.
Perhaps the most valuable chapter is the one on risk, since it is the figures relating to this that cause the most uncertainty and anxiety. A statement like “risk up by 42 per cent” sounds scientific and authoritative but tells us nothing useful (42 per cent of what?) or helps us answer the questions we want to ask: “Does that mean me?” and “What should I do?” The straight- forward way to bring this back into line with personal experience is to use natural frequencies – so many people per 100 or 10,000 or one million. The underlying message of the book, one that every politician and journalist should have drilled into them, is that life is messy and complicated, and that looking for certainty in the numbers that are produced is a waste of time. Truly it has been said: “If you ask a question, statistics will tell you the answer. What they won’t tell you is whether you asked the right question.”