Thank you for downloading from the BBC. The details of our complete range of

podcasts and our terms of use go to BBCWorldService.com slash podcasts.

You're listening to a download from the BBC. This is more or less the mathematical

icing on the cake of life. We make an addition of the program for BBC Radio 4 but

this is a download of a special edition broadcast on the world's service. Hello

and welcome to more or less on the BBC World Service. We are weekly guide to

the numbers in the news and in life and I'm Tim Halford. It's hard to think of a

more important figure than the number of people living in poverty. For many years

now a common standard for extreme poverty has been living on less than a

dollar a day and the estimates of who lives in extreme poverty have just been

updated. In its shocking simplicity the dollar a day measure has probably done

more to raise awareness of world poverty than any other effort. We

certainly intended to have some impact with it try to make reasonably well-heeled

people all over the world understand just how poor many people in the world are.

But how did this simple number which has acquired such power come about? We've

been following the trail and we've discovered it's much more complicated and

controversial a number than most people realize. It's a successful failure.

It's a wildly successful PR device that I think has been actually been a failure

in terms of achieving the objectives of improving human well-being in the world.

But first let's find out where the story starts Ruth Alexander's here. The

story starts at the World Bank in Washington DC in the late 1980s. Economists

then noticed that the national poverty lines of a number of developing

...