"Research on inequality usually keeps track of percentiles. So let's look at the following simple example. A society at the beginning consists of 10 individuals, 9 of which make 1 dollar and 1 who makes 10 dollars. Social scientists decide to keep track of the top 20%. So the top 20% makes an average of 5.5 dollars while the bottom 80% makes an average of 1 dollar. Now suppose that after 1 year there are now 8 people making 1 dollar and 2 people making 10 dollars. The top 20% now makes an average of 10 dollars. Dividing 4.5 by 5.5 this represents an 82% increase for the top quintile. The bottom 80% on the other hand sees a 0% increase in income. One would like to conclude that 'inequality has risen'. But if you were given a choice to live in a society like the earlier one with 9 people making the same income of 1 dollar and one very rich person making 10 dollars, or live in the latter society where less people make 1 dollar and more people make 10 dollar, what would you choose? A simple calculus of probability tells me that the latter society might be more appealing to most people."I offer this just as another illustration of my warning to beware the stories told based upon aggregation.
Monday, November 03, 2008
From CAFE HAYEK an illustration by Pietro Poggi-Corradini: