Scott Walker doesn’t need a degree — and neither do you

Yet despite their own blue-ribbon educations, these leaders are making a classic rookie blunder: They mistake correlation for causation. They point to study after study showing that Americans with college degrees do significantly better on a wide range of indicators: income, marriage, health, happiness, you name it. But they assume that it’s something about college itself that makes the difference, some alchemy at their alma mater that turns gangly 18-year-olds into twentysomething masters of the universe.

Sure, college can be a great experience, and many individuals gain important knowledge, skills, insights, and contacts there. It’s also a prerequisite for most graduate and professional schools. All of that can help to build the “human capital” that enables people to get good-paying jobs and then excel at them.

But much of the college advantage can be explained by “selection bias” — the differences between those who tend to complete college and those who don’t. The dirty little secret of college is that it tends to bestow a credential on those who are already most likely to succeed. To use another term from Statistics 101, it’s “instrumental variables” that explain why college grads do better: their reading and math abilities; their social skills; their wealth. If people with these underlying advantages did something with their time other than go to college — like start a business or serve in the military — they would still outperform their peers over the long term.