做因果发现的朋友可以看看，这篇把PC和FCI背后的CI检验方法按六个家族梳理清楚了，还讲了每种方法什么时候会失效，省得自己踩坑。
该综述系统梳理了约束因果发现中的条件独立性检验方法，涵盖PC和FCI算法中骨架剪枝与方向判定的核心环节。文章将CI测试分为偏相关、列联表、回归、最近邻、核和机器学习六大家族，并重点分析各族的鲁棒性局限。综述指出CI检验的统计功效随条件集规模增大而衰减，且I型/II型错误不对称会影响图级骨架恢复和v结构定向。文章还比较了主要R和Python库的采用情况，并总结了混合类型数据、小样本误差控制等开放挑战。
Conditional Independence Tests for Constraint-Based Causal Discovery: A Survey
Conditional Independence (CI) tests are the statistical engine of constraint-based causal discovery: in algorithms such as PC (Peter-Clark) and FCI (Fast Causal Inference), skeleton pruning and key orientations follow directly from CI decisions. This survey reviews CI testing with emphasis on assumptions, robustness, and scalability in high-dimensional and mixed-type settings common in biomedical domains. The survey organizes widely used CI methods into six families: partial-correlation, contingency-table, regression, nearest-neighbor, kernel, and machine-learning-based. Special emphasis is provided on the robustness layers that address the limitations of these families. For each family, the survey examines when CI decisions reflect the data-generating distribution and when they fail. By this, we link test-level properties, including power decay with conditioning set size and asymmetric type I/II error consequences, to graph-level errors in skeleton recovery and v-structure orientation. The survey also compares adoption across major R and Python libraries and summarizes open challenges, including mixed-type CI testing without discretization, small-sample error control, and strategies for improving scalability of CI-testing.