The current issue of The Atlantic carries a fascinating summary of “The Confidence Code” by Katty Kay and Claire Shipman. The essay runs through the evidence suggesting that women tend to have too little self-confidence. When asked how well they did on tests, women tend to estimate that they got fewer answers correct than they actually did. In one British study, a business school professor asked students how much they would deserve to earn five years after graduation. The women’s estimates were 20 percent lower than the men’s.