There has been an amusing debate I stumbled upon between Nobel laureate and New York Times columnist Paul Krugman and junior blogger, Iowahawk. The gist of the argument is around school performance in unionized Wisconsin and union-free Texas. If you look at raw ACT/SAT and dropout averages Texas looks downright grim, a “fact” also shared on the Economist‘s blog. But if you break the averages down by ethnicity, Texas beats Wisconsin and the national average for all ethnic groups. The reason one state can beat the other in all categories and lose out overall has to do with the proportion of each category in the population mix. This type of situation happens more than you might think. It even has a cool name: Simpson’s Paradox.
The point isn’t to get into an ideological debate but to show that the tyranny of averages can strike anywhere, even the pages of the Gray Lady and the Economist.