do you go ‘wow!’ at big numbers?

Quite probably – even though it’s quite hard to envisage what a really really big number means.

But people can also be swayed by big numbers when they shouldn’t be. Ben Goldacre gives an example in his latest post. A media story about a particular statin (a drug used to lower the levels of ‘bad’ cholesterol) reported that it lowered the risks of heart attack by 54%. Sounds good.

But hang on a minute – 54% of what? Before you can assess how good this statin is, you need to know the risk of heart attack for people not on the drug. The actual trial was looking at using the statin as a preventative in people who were already at low risk of having a heart attack. It turns out that in this group the relative risk was 0.37 events ‘per 100 person years’. For those on the drug, this dropped to 0.17. Yes, it was indeed a 54% reduction in relative risk – but off a low base in the first place…

Ben concludes: We all love big numbers, and we’re all fooled by big numbers, because we’re all idiots. That’s why it’s important to think clearly, and ignore all newspapers.

(I don’t know if I’d go that far – but you do need to think very clearly indeed about what you read.)

4 thoughts on “do you go ‘wow!’ at big numbers?”

  • Naturally, being a humble English Lit student with a passion for science, I won’t have any access to the original article. However, I always appreciate good commentary on research. I look forward to any future post you make. A lot. DI are a fascinating and disturbing lot, I’ll be quite interested to see if ID campaigning picks up under the incoming Government, seeing how they’re willing to exploit endorsements from theo-lobbyists like Family First (via Michael Jones and Inga Tuigamala).

  • Oops. I posted this comment in the wrong thread. It was meant for the Chimps post. Tabbed browsing *does* have disadvantages!
    Thanks for the compliment over on Open Parachute. 😀

  • Alison Campbell says:

    I’m really glad that you’ve joined the group over at Ken’s place. You put things so well (& so firmly!); I’m sure many others there appreciate your presence as well! (Although, perhaps, not James 😉 )

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