Chip Heath and Karla Starr have a book on communicating numbers. It makes a lot of sensible points. Some might seem obvious but it is easy to get these sort of things wrong. I certainly have in the past, so the advice is worth paying attention to. They even put a mention into their book for Dollywood — we have spent more than our fair share of time at that theme park — so what is not to like?
Use Helpful Comparisons
The authors tell us about fathoms — a useful point of comparison.
Find your fathom: Help people understand through simple, familiar comparisons. If you want to help people understand quickly, define your new concept in terms of something your audience already knows.Heath and Starr, 2022, page 29
BTW a fathom is the length of outstretched arms from finger tip to finger tip. They also tell us that a cubit is the length of a forearm. These are popular measures across cultures which makes sense seeing as these (rough) distances would be familiar to people.
To be most useful the fathom has got to be familiar and the right scale. Ideally, it’ll be roughly the same size as the comparison. If you are talking to an English person saying Iceland has a population around the same as Leciester might work. Saying Iceland’s population is about a 60th of the population of Chengdu is pretty useless. You just invite lots more questions and visualization problems: Is Chengdu big? What does a 60th look like?
Round, And Round, The Numbers
They give advice to round the numbers. People intuitively understand (most) whole numbers; fractions and decimals are less widely appreciated. I remember when I was first working at the Labour Party my boss at the time was keen to communicate the breakdown of our income: 40:30:20:10. (Membership, Trade Unions, Major Gifts, and Commercial/Other). Even at the time I basically appreciated that he was right but as a young accountant, I couldn’t shake the desire to say 31.2% or 19.1%. Of course, no one cared about the distinction between 19.1% and 20%. One percent, either way, didn’t impact the message. If I used ‘messy’ numbers this would just mean that no one would get the message. Always be careful that you don’t deceive with rounding, but do use rounding when it will likely help you effectively communicate a truthful point.
Communicating Numbers: Your Audience Matters
One of the central points they make — and it is sensible general marketing advice — is to know your audience. Things that make sense to some people will appear impenetrable to others. Ironically, the authors spend a lot of time explaining how shocked we should all be about how good LeBron James is at basketball and provide an illustration. I know he is good, because I’ve heard of him and I know hardly any basketball players. Still, their attempts to communicate this with how many points he scored per game left me cold. Is the amount he scores per game a lot? I didn’t feel they got that one across to me. (To be fair, I don’t think they should write their book for an audience of just me).
Returning to rounding this is probably more usefully applied than one might think. Even experts like simplicity. Why should they have to think more than they need to? They often won’t think. Have you ever had a paper reviewed by academic experts and thought that the reviewer seemed to be skimming on thoughtful analysis? (A shocking idea I know). You can’t change people so don’t even try and make them think when they shouldn’t have to.
Show And Tell
The story of the Glove Shrine was excellent. To illustrate the mess that was procurement in a firm an executive found one of all the different types of gloves that the company bought. He added prices to them and displayed them. The prices were all over the place; lots of similar gloves were bought from different suppliers at widely varying prices. The Glove Shrine just illustrated very tangibly that something needed to be done about how the organization bought supplies. Gloves weren’t the key thing at this firm but the point was clear. If glove buying is a mess what other procurement is? The neat illustration worked.