One pervasive task found throughout the empirical sciences is to determine the effect of interventions from non-experimental data. It is well-understood that assumptions are necessary to perform causal inferences, which are commonly articulated through causal diagrams (Pearl, 2000). Despite the power of this approach, there are settings where the knowledge necessary to specify a causal diagram over all observed variables may not be available, particularly in complex, high-dimensional domains. In this paper, we introduce a new type of graphical model called cluster causal diagrams (for short, C-DAGs) that allows for the partial specification of relationships among variables based on limited prior knowledge, alleviating the stringent requirement of specifying a full causal diagram. A C-DAG specifies relationships between clusters of variables, while the relationships between the variables within a cluster are left unspecified. We develop the foundations and machinery for valid causal inferences over C-DAGs. In particular, we first define a new version of the d-separation criterion and prove its soundness and completeness. Secondly, we extend these new separation rules and prove the validity of the corresponding do-calculus. Lastly, we show that a standard identification algorithm is sound and complete to systematically compute causal effects from observational data given a C-DAG.

该研究介绍了一种叫做“集群有向无环图（Cluster DAGs）”的新型图形建模工具，其可以基于有限的先验知识提供变量之间关系的部分规范，从而缓解了在复杂、高维度领域中指定完全因果图的严格要求。在该图形模型下，本研究还开发了基于“Pearl's Causal Hierarchy”的各层级的变量集聚进行推理的方法，并验证了C-DAGs的有效性。

聚类DAG中的因果效应识别