Height and income

Some folks at Princeton have found, using panel data from England, that each additional inch in height is associated with 1.5-1.8% more wage income. Their suggested mechanism is having wealthy parents that feed their kids right and make sure they get more and better education leads to taller and better paid kids.

Its strange to me that to test the hypothesis that having wealthy parents leads to better economic outcomes, e.g. income, education, etc — a list of dependent variables that gets longer as Economics’ empire expands — these researchers had to use height data as a proxy for parental income. Economic historians often use height as a health, and thus an income, proxy because its very hard to find direct measures of wealth and income. This is an ok proxy because its plausible in the Malthusian period most variation in height was caused by variation in nutrition and its plausible that most of that variation was due to differences in wealth. In the modern context, most variation in height is due to genetic factors (I think… razib?) and I’m guessing most variation in nutrition are due to social factors (of which income group is one of many). Height, then, is a terrible proxy for parental income in the modern period.

For a modern test of this hypothesis, getting direct measures of parental income has to be a least as easy as getting height data. Why not directly test their hypothesis? At most, these guys have found evidence that doesn’t contradict their hypothesis. But random noise doesn’t contradict it either. Which is to say they haven’t moved me far from my priors.

Historians are bold with their findings, often telling a story of a long causal chain using a single correlation or two. I don’t mind it when they do this because they’re not working with much and not to mention, from my experience, it makes them colorful folk. Labor economists don’t and shouldn’t have this luxury.

(h/t economist)