Domain Knowledge in A*-Based Causal Discovery

TL;DR

This paper explores how incorporating domain knowledge into A*-based causal discovery can significantly enhance efficiency and accuracy, especially when prior knowledge is available, addressing limitations of previous methods.

Contribution

It introduces methods for integrating various types of domain knowledge into A*-based causal discovery, demonstrating computational and performance improvements.

Findings

Domain knowledge reduces search space in causal discovery.

Incorporating domain knowledge speeds up A*-based algorithms.

Small amounts of domain knowledge improve accuracy and practicality.

Abstract

Causal discovery has become a vital tool for scientists and practitioners wanting to discover causal relationships from observational data. While most previous approaches to causal discovery have implicitly assumed that no expert domain knowledge is available, practitioners can often provide such domain knowledge from prior experience. Recent work has incorporated domain knowledge into constraint-based causal discovery. The majority of such constraint-based methods, however, assume causal faithfulness, which has been shown to be frequently violated in practice. Consequently, there has been renewed attention towards exact-search score-based causal discovery methods, which do not assume causal faithfulness, such as A*-based methods. However, there has been no consideration of these methods in the context of domain knowledge. In this work, we focus on efficiently integrating several types of domain knowledge into A*-based causal discovery. In doing so, we discuss and explain how domain knowledge can reduce the graph search space and then provide an analysis of the potential computational gains. We support these findings with experiments on synthetic and real data, showing that even small amounts of domain knowledge can dramatically speed up A*-based causal discovery and improve its performance and practicality.