Guido Imbens published a new working paper in which he develops a detailed comparison of the potential outcomes framework (PO) and directed acyclic graphs (DAG) for causal inference in econometrics. I really appreciate this paper, because it introduces a broader audience in economics to DAGs and highlights the complementarity of both approaches for applied econometric work.
I have a couple of comments on specific points in the paper though, which I wrote down in several Twitter threads throughout the last weeks. I chose Twitter, because we had many, quite extensive, discussions about DAGs there in recent months (Guido even cites some of our tweets in his paper) and because many economists seem to be active on this platform these days. Tansferring all these threads into blog posts would – frankly – require too much time. But for archiving purposes, I will link to the start tweets of the individual threads here.
(I have also saved the full threads as text files in my documents. So if you don’t like going through them on Twitter, or maybe they will be deleted one day, you can always shoot me a meassge and I will send them to you.)