Causal Inference, Instrumental Variables, Stats 361, Stanford, Data Science.
(2020), the image of the conditions Z has to satisfy can be more clear. “Z_i must be exogenous”; In the DAG, it means there is no confounding variable like L. “Z_i must be relevant, such that Cov[W_i, Z_i]≠0 “; In the DAG, there is an edge from Z to educ . “Z_i must satisfy the exclusion