How come I don’t know anyone who has been polled?

Variations on ‘I’ve never been polled and I don’t know anyone who ever has been’ are common amongst people sceptical about opinion polls. Who are the polls asking and can they be trusted if you don’t know anyone who has been polled?

Yes they can, and here’s why.

The most important reason is that polls do not need to encompass very many people in order to be accurate. A national poll typically needs only around 1,000 participants (see my piece here on why 1,000 samples are sufficient).

In the UK with an adult population of over 50 million, that means random chance would give you a less than 1 in 50,000 chance of being included in any one poll. (For a similar calculation from the US, see the Pew Research Center.)

Of course, lots of polls take place. So let’s extend that. There are currently 28 pollsters who are members of the industry self-regulatory body for polling. But there are other pollsters, so let’s call that 50 polling firms. Let’s also assume, generously, that each does a poll a week. That gives in round numbers 2,500 polls a year.

What’s your chance of never being polled in a year then, assuming those polls pick adults at random? It’s more than 19 chances in 20.

That’s pretty low.

But the real chances are lower still because polls aren’t fully random.

Most polls these days are done via internet panels, which means you have to have opted in at some point to be willing to take part in online polls. A smaller number of polls are via the phone, which means you either need to have a landline number (as these can be called at random) or you have to have opted to hand over your mobile phone number for such surveys at some point. An even smaller proportion of polling is done face-to-face, but these surveys are slow and expensive and so very rare.

So that’s why it’s not a surprise if you haven’t been polled. Nor is it much of a surprise if people close to you haven’t been either. (Though in addition, how sure are you really that you don’t know someone who has been polled – have you asked everyone?)

NOW AVAILABLE: Polling Unpacked: the history, uses and abuses of political opinion polls which, according to the Sunday Times, is “Essential reading for anyone seeking to understand modern politics … comprehensive yet surprisingly fun”.