Implementing my diff-in-diff checklist for the book using county level crime data

It’s ten days until the day I’m shipping off the mixtape second edition to Yale. I’ve been writing it for the last two years. The last several months have been increasingly intensive and the last six weeks have felt like permanent sleeplessness and 24/7 writing. When I finish, I am contemplating printing out all of my final exams and final projects for my history of thought class, and camping at Big Bend and take a long needed break. I am deeply pleased with the new book though, and so excited to be moving on to produce a new version of the online book.

One of the things that I do in the book that is new is the diff in diff checklist. I got this from the Roth, et al (2023) “What’s Trending in Diff-in-Diff”, a checklist that Pedro Sant’Anna circulated and a tongue in cheek slide by Guido Imbens (step 9). It’s a step by step that I follow using county level crime data to estimate the effect of concealed carry laws on murders based on a dataset that John Donohue collected.