Title
Shapley Values and Meta-Explanations for Probabilistic Graphical Model Inference
Abstract
Probabilistic graphical models, such as Markov random fields (MRF), exploit dependencies among random variables to model a rich family of joint probability distributions. Inference algorithms, such as belief propagation (BP), can effectively compute the marginal posteriors for decision making. Nonetheless, inferences involve sophisticated probability calculations and are difficult for humans to interpret. Among all existing explanation methods for MRFs, no method is designed for fair attributions of an inference outcome to elements on the MRF where the inference takes place. Shapley values provide rigorous attributions but so far have not been studied on MRFs. We thus define Shapley values for MRFs to capture both probabilistic and topological contributions of the variables on MRFs. We theoretically characterize the new definition regarding independence, equal contribution, additivity, and submodularity. As brute-force computation of the Shapley values is challenging, we propose GraphShapley, an approximation algorithm that exploits the decomposability of Shapley values, the structure of MRFs, and the iterative nature of BP inference to speed up the computation. In practice, we propose meta-explanations to explain the Shapley values and make them more accessible and trustworthy to human users. On four synthetic and nine real-world MRFs, we demonstrate that GraphShapley generates sensible and practical explanations.
Year
DOI
Venue
2020
10.1145/3340531.3411881
CIKM '20: The 29th ACM International Conference on Information and Knowledge Management Virtual Event Ireland October, 2020
DocType
ISBN
Citations 
Conference
978-1-4503-6859-9
0
PageRank 
References 
Authors
0.34
0
5
Name
Order
Citations
PageRank
Yifei Liu100.34
Chen Chao2223.99
Yazheng Liu300.34
Xi Zhang412.06
Sihong Xie548333.80