Neither raw intelligence nor years of experience reliably predicts elite performance

Colvin surveys research showing that measures we'd expect to correlate strongly with expertise — general intelligence, or simple years spent doing a job — turn out to be weak predictors once you look closely at actual performance outcomes. Chess masters, musicians, and business leaders show only a loose relationship between raw cognitive test scores and how good they actually become at their specific domain.

Even more striking is the experience finding: doctors who have practiced for twenty years are not reliably better diagnosticians than doctors fresh out of training, and in some studies perform worse, because mere repetition without deliberate correction doesn't sharpen skill — it can calcify existing habits, including bad ones. Years on the job measure exposure, not necessarily improvement.

Colvin uses this to dismantle two comforting assumptions at once: that smart people naturally become experts, and that simply doing a job long enough guarantees mastery. Both intuitions, he argues, mistake proxies for the real driver of skill. Takeaway: time served and IQ are not substitutes for structured, corrective practice.