What's wrong with research in the social sciences?

What's wrong with research in the social sciences? Only two things. How it's done and how it's interpreted.

A few weeks ago, some economists, Raj Chetty (Harvard), John Friedman (Harvard), Nathaniel Hilger (Harvard), Emmanuel Saez (UC-Berkeley and winner of the John Bates Clark Award), Diane Schanzenbach (Northwestern) and Danny Yagan (Harvard) gave a talk on their research project. They were trying to find out if your kindergarten experience has much of a lasting effect. Previous research...