A New Causal Decomposition Paradigm towards Health Equity

Causal decomposition has provided a powerful tool to analyze health disparity problems by assessing the proportion of disparity caused by each mediator (the variable that mediates the effect of the exposure on the health outcome). However, most of these methods lack policy implications, as they fail to account for all sources of disparities caused by the mediator. Besides, its identifiability needs to specify a set to be admissible to make the strong ignorability condition hold, which can be problematic as some variables in this set may induce new spurious features. To resolve these issues, under the framework of the structural causal model, we propose a new decomposition, dubbed as adjusted and unadjusted effects, which is able to include all types of disparity by adjusting each mediator’s distribution from the disadvantaged group to the advantaged ones. Besides, by learning the maximal ancestral graph and implementing causal discovery from heterogeneous data, we can identify the admissible set, followed by an efficient algorithm for estimation. The theoretical correctness and efficacy of our method are demonstrated using a synthetic dataset and a common spine disease dataset.