Can Z be an instrument given this DAG? X is endogenous, and Z is endogenous wrt to X. I believe Z cannot be an instrument in this case, right? I don't know much about DAGs yet, but I am trying to learn. @causalinf thanks!
also, the following DAG a definite no for z to be an instrument, right?
You can follow @dade_us.
Tip: mention @twtextapp on a Twitter thread with the keyword “unroll” to get a link to it.

Latest Threads Unrolled: