Causality in the Spotlight: Height, BMI, and Socioeconomic Status

If you are a regular reader of our blog, you know our mantra that "correlation is not causation." And, when we found this article in Elite Daily which proclaimed "If You Have These Physical Traits, You Are More Likely to Make Less Money," you can imagine our everydata radar went up.  The story explains that taller men were more likely to earn more money and to work in high-status jobs.

Although there are some issues with the self-reported metrics of income and job outcomes, it turns out the underlying study though applied a very interesting and creative idea to try and isolate a true CAUSAL relationship between work outcomes and height and BMI.  The authors used a series of randomly determined genetic markers that make individuals pre-disposed to being taller or heavier.  What is great about this design is that it allows the researchers to try to isolate a causal link--genetic markers are not correlated with any of the other factors that might effect job outcomes ostensibly.  

So, this time, I can happily report that there is something to be learned from this article.  Now, there is a lot of nuance-- particularly noteworthy is that relative to the simple correlations, the "genetic" marker indicators lead to much smaller effects of these factors.  But, its great to see a study taking causation seriously.