Monday, January 27, 2020

Test Post: Number in Absolute Poverty vs. Proportion in Absolute Poverty

I believe this will finally show as intended. I do not expect this to last. I fully blame short-sighted bureaucrats in the European Union, and their enforcers the large internet companies. If the images posted here disappear, or the post itself does, blame them, not Dr. Tufte. Everything I've done here has always been covered by the doctrine of fair use.

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The World Bank defines poverty on an absolute scale.† Here’s some snapshots (sorry about the quality, it was tough to get these out of a protected format):

The above shows the improvement in number of people living in absolute poverty. Below is a repeat from what we looked at in class on Friday (so that we have them on the same page). It shows the proportion of people in absolute poverty.

And here is an image from another source that shows that the number of people in absolute poverty got worse for a while (as people lived longer and population went up), but that has been overcome by reducing the proportion in poverty over the last few decades.

This is a phenomenon taking place in most countries around the globe. But the numbers will be dominated by changes in China (bigger improvements over more people) and India (pretty good improvements over a lot of people, but not as pervasive as in China), due to their large populations.
† If you don’t know the difference between absolute and relative poverty, you should get this down cold (economists have to know this because there are lots of non-economists that don’t and could probably use our help).
Absolute poverty means you define a level of stuff or some real currency threshold that is fixed or constant. (Keep in mind that if you’re using a real currency threshold, that may change when you change base years). Anyway, if you exceed that threshold you’re no longer poor. The World Bank, since 1990, has been using a real currency threshold to assess absolute poverty globally. As of 2015, this was set to $1.90/day, or about $700/year in PPP real GDP per capita. I believe those PPP dollars are calculated using the Geary-Khamis method, using a base year of 2011 (that sentence isn’t stuff you have to know, but if you see those words now you do).
Relative poverty means you define a proportion of what most people have as the the threshold. For this, it doesn’t matter whether you choose a real or nominal value to start with. It may matter whether you choose a mean, median, or some percentile value to start with (because the income distribution isn’t a nicely behaved bell curve anywhere). For example, you might say that the poverty threshold is 50% of median income. In the U.S., the poverty threshold is set by the Census Bureau. The calculation is more finely grained than that, but that’s the basics.
The advantage of using absolute poverty as a measure is we know if people’s basic needs are likely to be met. The disadvantage is we don’t know how far poor people are away from typical people. The advantage of relative poverty is we know roughly how many people are disadvantaged relative to those around them. The disadvantage is that this is a sliding scale: as a country gets richer, the threshold for poverty goes up, and can be difficult to compare across regions and times.
More practically, absolute poverty can be eliminated, but it doesn’t mean that there won’t still be people who are worse off. Alternatively, one might be able to eliminate relative poverty, but since the threshold generally increases with the passage of time this almost never happens.

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