Accuracy vs Precision

Today's XKCD;

I'd be inclined to take this a step further; when you say "people are stupid compared to your expectations", what you are really saying is that my expectations of how smart people are is constantly and consistently wrong, yet I am unwilling to change my expectation to accomodate this information.

One of the things that stuck with me from my degree 1 is the idea of "Accuracy" vs "Precision."

Precision is essentially about consistency – a repeated measurement will give very similar values. Accuracy is about a measurement being close to a "true" value. So, a measurement using an incorrectly calibrated set of weighing scales can be very precise (always reporting the same weight), but not very accurate. Or reporting a figure to a large number of decimal places can be a very precise measurement – but that doesn't mean that it is an accurate one.

So, the "people are stupid" statement could be taken as saying that your views are not accurate, you know that they are not accurate, you know how you could change your views – but you refuse to. Perhaps to maintain your belief in your own level of relative 'smartness'.

Which, I guess, is pretty stupid…


It also reminds me of my favourite George Carlin quote – Think about how stupid the average person is. Then realise that half of the population is more stupid than that. 2

  1. I studied Chemisty with Environmental Chemistry. On one hand, I probably should have switched to a topic I found more interesting when I realised that I wasn't going to maintain a keen interest for 3 years. On the other hand, I'm not sure I would have necessarily made a better choice.

  2. Of course, if you interpret "average" to mean "mean", then this assumes that stupidity/smartness is normally distributed, and the mean and median are the same – which is not necessarily true.