If I don’t finish this column today, I’m in big trouble: I’ll be writing it on holiday, and my wife is likely to club me to death with a rolled-up copy of the FT’s glossy How to Spend It magazine. She’s always telling me that I work too hard, and she may well be right. But what would happen to the economy if we all took life a little bit easier?

The simple answer is that we’d all produce less, which would mean more time to relax and fewer material goods to enjoy. The economy, as measured by gross domestic product, or GDP, would shrink. That would be just fine, of course.

GDP measures the total financial value of all the goods and services produced in an economy over the course of one year. Evidently, therefore, it leaves a lot out. For instance, sex in the context of a loving relationship is generally regarded as a good thing. Yet it would not show up in the GDP figures; sex with a prostitute would do just that, at least in principle. For such reasons, I often see proposals for superior measures of national welfare that allow adjustments for many things, ranging from environmental degradation and arms trading to time spent commuting.

I find such proposals very odd.

When a hatter measures the circumference of your head, he’s trying to work out what size of hat would fit you. It’s true that he has failed to gauge accurately your intelligence, but if you made that complaint he’d be puzzled. He’d be even more puzzled if you started proposing various adjustments. The same with GDP: it was only ever intended to measure economic transactions and there’s not much point in accusing it of failing to measure something else.

But if GDP leaves out so much that matters, why do my fellow economists lavish so much attention on the latest quarterly GDP growth figures? (Are they, like the hatter, mad?) They do so because GDP growth tends to be correlated with good things: people who want jobs finding them; useful new ideas finding their way into everyday life. Falling GDP tends to be correlated with people going bankrupt or being fired. This is not inevitable, but the historical correlation has always been very strong.

If we all decided to take more holidays, the correlation between GDP and all that bankruptcy and misery would be broken.

It’s hard to say exactly how the adjustment would take place and how painful it might be - after all, in the real world we do not all simultaneously decide to kick back and relax - but there’s no reason to think it would cause much trouble.

We would all have more time and less money; the fall in each person’s ability to buy material goods should nicely match the fall in everybody else’s ability to produce those material goods.

The only puzzle, given how incredibly wealthy we are by the standards of our ancestors, is why more people don’t opt for the extra time instead of the extra money. Robert H Frank, an economist at Cornell University, argues that it is hard to do that unless many others do the same. In his new book, Falling Behind, he points out that it’s not just a case of enviously coveting as good a car as your neighbour’s. Your status or your dating prospects may be affected if you downshift and others do not. So would your ability to buy a house in a safe area with good schools.

Professor Frank is a case in point. Falling Behind hit the bookshops only six weeks after his excellent The Economic Naturalist. Two books in six weeks? And he’s telling me to take it easy?

Tim Harford’s book “The Undercover Economist” (Little, Brown) is out now in paperback.