I n the epilogue of their blockbuster book Mostly Harmless Econometrics (2009), Josh Angrist and Steve Pischke write, “If applied econometrics were easy, theorists would do it.” As academic jokes go, ...

When gasoline is expensive, people grumble that big oil companies like Chevron and ExxonMobil are colluding to keep prices high. They’re wrong. The best way to understand why businesses aren’t ...