BBC NEWS | Magazine | Putting percentages in context
Percentages might make news stories stand out, but without a connection to the human experience, can become meaningless. Wouldnt it be good to have the mental agility to separate the wheat from the chaff? In his third lesson of a weekly series, author Michael Blastland gives some hints for percentages.
Interesting little article, though I cringed at the part where he said: “And let’s keep percentages out of it, as far as we can.
The answer is that in every 100 men aged 75, four or more will typically die in the next year. If all 100 of them tuck heartily into Vitamin E, maybe five will. ”
Do that many ppl really not know that a percentage is just a fraction, one that can be written as number/100? So the paragraph above could easily (and accurately) be written as “for men aged 75, at least 4% will typically die in the next year”. Surely that would be the way to take the mystery out of percentages - to write out what the real words are, and what the percentages are alongside them.
His final paragraph touches on this:
A percentage is not really a number, it is a share. The simple question to keep in mind is one that always strives to put it into a proper, human context: “A share of what? A share of a lot - or a share of a little?” Better still: “A share of who?”
but doesn’t really go far enough into explaining it, so I can’t feel that he’s really covered the basic facts here. Or perhaps he thought it would be too scary?
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Yes, but the stat would actually be worded thus:
“Excessive consumption of vitamin E increases the chances of a 75-year-old man dying in the next year, by 25%.” Which it does - it takes it from 4% to 5%. It’s phrases like “doubles the chance” that confuses people, in situations where we’re actually talking about a tiny risk increasing to a slightly less tiny one.
“in every 100 men aged 75, four or more will typically die in the next year”
What does that mean? Does it mean 4%? Or does it, as it equally might, mean 6%, or 100%?
It has only been in my adult life that I have properly understood percentages/fractions/decimals - thanks to my good partner. I got O level maths, and a grade A at that, but I just learned the manipulations I was taught. It was honestly only in the last few months that I realised, “Oh, a fraction is a division sum - not just a piece of cake!”
I do read with a critical eye, thanks to some stuff about the use of stats that I read when doing my sociology degree, but still get utterly confused at times. I feel completely ignorant about economics, where percentages crop up all the time. My favourite use, though, is in commercials for ‘beauty products’ where up to 75% of women said their skin was more radiant, and so on… They’re great.
Thought you might be interested in this short omega-3 video:
No thanks, Susan, we’re not interested in spammers here.
“lies, damned lies and statistics”