By now, there are many free resources with a focus on empirical methods in economics. On this page we list some of the best and most important pages. If you miss any, drop us an email or comment below!
Scott Cunningham’s The Mixtape
Nick Huntington-Klein’s The effect book
Martin Huber’s Causal Analysis (donation required)
Christine Cai’s Recent Advances in Applied Micro Methods
American Economic Association – Committee for Economic Education: Econometrics Handbook