Not all that many people are aware of quite how appallingly bad most economics statistics are. Not in the sense of it's terrible that the numbers are as they are, but that the numbers are generally so shoddily lashed together. And this is obviously going to be even more true in hte poorer parts of the world. A government that hasn't quite worked out how to collect the rubbish isn't going to be all that good at counting the people nor what they do or earn.
The upshot of this is that we really don't know how many poor people there are out there. We know there are fewer than there used to be, and the poor are a very much smaller portion of the growing population than used to be true, but we really only know trends rather than actual numbers. Basically because the numbers we've got for things like GDP and inequality are so sketchy themselves.
So, enter another method of trying to measure things. What's one of the first things someone will do when they've finally got a couple of annas to rub together? Get in an electric light bulb, So, let us measure the amount of light that we can see from space and we can have a good stab at working out whither poverty. Which is exactly what this paper does:
Finally, we use the new optimal measure of true income to calculate the evolution of poverty at the worldwide level as well as at the regional level. Given that our optimal measure gives a small weight to survey means, our optimal estimates of poverty rates tend to be closer to those reported in the research that uses GDP as the anchor. Under our procedure, developing world poverty declines from 11.8% in 1992 to 6.1% in 2005 and 4.5% in 2010, much lower than the path constructed by giving a weight of 1 to the surveys, which entails poverty falling from 42% to 20.5% between 1992 and 2010. We run a battery of robustness checks on our findings; under the ones most favourable to replicating the survey-based results, the largest that we find developing world poverty to be in 2010 is 12%.
Excellent, things are better than we thought they were.
It's worth making on other point about the differences in these methods of measurement. There are those who insist that those developing economies need to be planned. The smack of firm government must guide their economy. But as we can see, the governments don't actually have the information they would need to be able to plan, even if this were desirable. So it's a doubly bad idea.