Sound and Complete Causal Identification with Latent Variables Given Local Background Knowledge

Tian-Zuo Wang, Tian Qin, Zhi-Hua Zhou

Keywords: background knowledge, partial ancestral graph

TL;DR: We study what causal relations are identifiable given local background knowledge in the presence of latent confounders.

Abstract: Great efforts have been devoted to causal discovery from observational data, and it is well known that introducing some background knowledge attained from experiments or human expertise can be very helpful. However, it remains unknown that \emph{what causal relations are identifiable given background knowledge in the presence of latent confounders}. In this paper, we solve the problem with sound and complete orientation rules when the background knowledge is given in a \emph{local} form. Furthermore, based on the solution to the problem, this paper proposes a general active learning framework for causal discovery in the presence of latent confounders, with its effectiveness and efficiency validated by experiments.