Visual Analysis of Multi-outcome Causal Graphs
Mengjie Fan, Jinlu Yu, Daniel Weiskopf, Nan Cao, Huai-Yu Wang, Liang Zhou
TL;DR
The paper addresses visual analysis for multi-outcome causal graphs in health research, enabling comparative analysis across diseases. It proposes a two-stage workflow: progressive visualization for single-outcome causal discovery using PC, DAG-GNN, and HCM, followed by a comparative layout and visual encodings to compare multiple outcomes. The approach is validated with benchmark datasets, case studies on UKB and CLHLS, and expert-user evaluations, demonstrating improved interpretability and cross-outcome insights. The work provides publicly available code and lays groundwork for extending causal analysis in healthcare and other domains.
Abstract
We introduce a visual analysis method for multiple causal graphs with different outcome variables, namely, multi-outcome causal graphs. Multi-outcome causal graphs are important in healthcare for understanding multimorbidity and comorbidity. To support the visual analysis, we collaborated with medical experts to devise two comparative visualization techniques at different stages of the analysis process. First, a progressive visualization method is proposed for comparing multiple state-of-the-art causal discovery algorithms. The method can handle mixed-type datasets comprising both continuous and categorical variables and assist in the creation of a fine-tuned causal graph of a single outcome. Second, a comparative graph layout technique and specialized visual encodings are devised for the quick comparison of multiple causal graphs. In our visual analysis approach, analysts start by building individual causal graphs for each outcome variable, and then, multi-outcome causal graphs are generated and visualized with our comparative technique for analyzing differences and commonalities of these causal graphs. Evaluation includes quantitative measurements on benchmark datasets, a case study with a medical expert, and expert user studies with real-world health research data.
