Hello and welcome to the More or Less podcast with me, Tim Halford.

This week another chance to hear some classics from the More or Less archive

that are relevant to the news of the week.

Two are about sex and one is about the economics of royal babies.

This week it was widely reported that people in the UK seem to be having less sex,

which made this question seem rather pertinent.

Can we ever trust statistics about sex in relationships?

Sir David Schpiegelhalter, Cambridge University's professor for the public understanding of risk,

has written a book called Sex by Numbers.

But it's not just a book about sex, it's also a book about the way different statistical claims

about sex should be viewed very differently.

Indeed, he's created a system to rank how seriously we should take sex statistics.

We know there's lots of sex going on, but we can't count it like we can count road accidents

or something like that.

We have to either ask people in which case we have to try really hard to get accurate answers

or kind of infer behaviour from official statistics that we can believe.

But of course many of the statistics that get reported about sex, if you just go onto the internet,

there's endless lists of sex statistics and most of them are pretty bad.

And so what I've done is try to make a attempt to grade the numbers that we hear.

So if we think of the best ones, I call them four star statistics.

Four star statistics we can actually really believe them.

There are official numbers, births, marriages, divorces, abortions, we know those, we can count those.

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