I once had a wonderful relationship with numbers. They went from zero to as high as you could count. They knew their place: Two followed one; six-hundred-and-eleven was before six-hundred-and-twelve. It was a perfectly ordered world. Numbers were just numbers.
Then I met ‘X’.
‘X’ was in a maths class, and it had usurped one of the numbers in a simple problem. But ‘X’ wasn’t actually a number — it was a shifting value, as slippery as an eel (if fish were used in algebra). This revelation put me off numbers. Hey, if ‘I’ was really the square root of minus one and imaginary to boot, I wasn’t going to make the effort.
I refused to use numbers that didn’t even exist. Now I see that the world can be divided into two groups: Those who can deal with imaginary numbers, and those who can’t. I would politely suggest that the latter group outnumbers the former.
That’s a huge problem when having to present numbers. We have difficulty judging relative size, percentages and probability, which is why we buy lottery tickets. Spoiler alert: If we understood probability, then we wouldn’t bother with the lottery.
So how do you present numbers effectively so that everyone understands your point?
1. Use the ‘Wales Scale’
The Wales Scale is the predominant scale used in the UK. It’s a scale that covers height, length and area. It has a number of units. Area is measured in tennis courts, football pitches and proportions of ‘The size of Wales’ as in ‘It’s twice the size of Wales’. Length is usually done in London busses, but they can also be a unit of height. Height starts off with Nelson’s Column as the lowest unit and Mount Everest the highest. All of these measurements are concrete, and people can pin images to them. We know how big Wales is and everyone has seen a London bus. Numbers become familiar images in the brain.
There is one problem, however. The ‘Wales Scale’ serves a very specific audience, so if you’re presenting a global webinar or to an international audience, consider your audience’s frame of reference. For example, the population of The Netherlands would be a bad choice. I’m not sure many Europeans know what the population of The Netherlands is let alone anyone from another continent. Find your own audience-appropriate scale and create pictures to make the numbers real.
2. Don’t hide the truth in percentages
How many times have you been in a meeting and someone reports “200% growth quarter on quarter” or something equally stunning? Everyone nods in approval and you feel all warm and toasty because something has grown by 200%. Then you get back to the office to look at the figures more closely. Yes, the growth was 200%, but that simply means one customer is now three customers — certainly not as impressive, and this realisation makes you feel a bit cheated.
If you try this clever tactic in your own presentation, your audience will probably feel the same way. Don’t try to hide figures in a mass of percentages. This allows our mathematical ignorance to do the work of a lie.
3. Simplify the sorites paradox
Imagine you have a heap of sand and you remove the sand grain by grain. Eventually you’ll no longer have a heap. The sorites paradox describes the problem of vague language. The heap has gone but which grain of sand removed the heap? When does it become ‘some sand’? Language is our way into numbers but shouldn’t replace the numbers.
Doubled we understand, but increased by 100% is getting a little bit too complicated. Have the number behind you on a slide, but use words like ‘most’, ‘almost everyone’, ‘not very many’, or ‘fewer than expected’. Let words support the numbers, but remember, don’t let them lie for you. 51% is just over half; 51% is not most.
This isn’t just a guide to presenting numbers effectively; this is a guide to listening. No one wants to be asked “Is that a big number?” halfway through telling you about their 500% growth figures.