The Simple Power of The 2x2: Personal Reflection on Difference-in-Differences

This is a bit of a rambling post. It starts out about diff-in-diff, but then gets personal, and then gets back to diff-in-diff. Which means I started out wanting to write one thing, and then wrote something else. But I have made myself sick again, and just probably wrote through it this morning seeing stars in my mind.

And yet the discipline is to pay…