Media

Flip it around

Andrew Gelman Oct 4 '11

How does one interpret a comparison?

Stephen Dubner says:

If you’re a child who’s adopted into a high-education family — that is where the parents both went to college — you are about 16 percentage points more likely to go to college than a kid who gets adopted into a low-education family. So that sounds pretty good, OK? [emphasis added]

Let’s flip it around:

Taking the study’s results as correct, if you’re a child who’s adopted into a low-education family you are about 16 percentage points less likely to go to college than a kid who gets adopted into a high-education family.

16 percentage points lower—that sounds pretty bad, not pretty good!

This sort of thing comes up all the time. Country A is doing better than country B: That’s great! Country B is doing better than country A: That’s great too! It reminds me of the research by cognitive psychologists of framing effects (for example, the study involving a story in which 600 people were going to die and then told some people that “400 people would die” and others that “200 people would be saved.” People reacted very differently to the glass-half-full and glass-half-empty formulations.