Understanding numbers is vital to so many parts of life. It is a shame many otherwise sensible people don’t seem to take numbers seriously.
Numbers Allow You To Understand Magnitude
When I managed the finances of a political party the BBC’s political editor explained on TV that donations totaling 6 million pounds would run my party for a year. It was patently absurd. We needed around 30 million pounds a year; 20% is not really close to 100%. This was frustrating because our message was that we weren’t run by donations from millionaires. Our message was true but the journalist’s mistake made it look like it wasn’t.
Clearly, the political editor of the BBC didn’t think understanding political finances was important because it was just numbers. To be clear we published accounts. The political editor of the BBC didn’t seem to have bothered to look at the numbers. To my mind, ignoring the numbers couldn’t be more wrong. It is hard to look at budget negotiations, expense scandals, and funding crises without realizing that numbers matter in politics.
Meda Reporting of Numbers — Often Prety Awful
The media’s reporting of numbers is often a problem. For instance, Leonard Mlodinow makes the point that the imprecision of reports is often misunderstood. People think the headline number is the “truth” rather than the (hopefully) best estimate anyone can make given the information available.
“One recent August the Bureau of Labor Statistics reported that the unemployment rate stood at 4.7 percent. In July the bureau had reported the rate at 4.8 percent. The change prompted headlines like this one in The New York Times: “Jobs and Wages Increased Modestly Last Month”. … if the Bureau of Labour Statistics measures the unemployment rate in August and the repeats its measurement an hour later, by random error alone there is a good chance that the second measurement will differ from the first by at least a tenth of a percentage point. Would the New York Times then run the headline “Jobs and Wages Increased Modestly at 2P.M.”?”
Mlodinow, 2009, page 129-130
Understanding Numbers And Where They Come From
My advice: When reading numbers consider how the data is measured. Surveys will have at least some range associated with them. Don’t think of this as bad. Accepting some imprecision is necessary. Otherwise, you’d rarely estimate anything. That said we shouldn’t imbue the reported numbers with magical properties. 4.7% and 4.8% probably aren’t meaningfully different. If a political party is at 40% support and moves to 39% support this is almost certainly within a poll’s margin of error. It doesn’t mean much at all. If the numbers in your survey of customer satisfaction fall a tiny amount it really isn’t time to panic. Life is full of things we don’t totally understand, (randomness/error). The challenge is to focus only on meaningful changes, ideally ones we can do something about.
For more on numbers, numeracy, and nonsense see here, here, and here.
Read: Leonard Mlodinow, The Drunkard’s Walk: How Randomness Rules Our Lives, Vintage Books 2009.