In response to this:
Economists have known for some time that better-looking people are paid more. This is probably due to a combination of discrimination against the ugly, the fact that some beautiful people have jobs where beauty is an obvious advantage, and the likelihood that better-looking people are more confident.
More recently, economists have discovered evidence that endogenous beauty (make-up, hair-styling) is as important as exogenous beauty (having Bond girl Eva Green’s eyes).
An irate reader writes:
Much as we all like exogenous and endogenous as exotic (cf. endotic) words, they do have to be used the right way round. You would have been better to use a nurture / nature comparison; more sexy than external / internal which is what you really meant.
Not so. Exogenous does not mean "external"; it means "generated outside". And to an economist, it means determined by factors outside the system under consideration. In other words, you can put on make-up but you can’t improve your genes. So, make-up is "endogenous beauty" even though it is applied to the outside of the skin. Of course, all this is economic jargon. But when did "Dear Economist" not use economic jargon? It’s the whole point of the column.