Beyond TreeSHAP: Efficient Computation of Any-Order Shapley Interactions for Tree Ensembles

作者：Maximilian Muschalik, Fabian Fumagalli, Barbara Hammer, Eyke Hüllermeier · 发表于：AAAI Conference on Artificial Intelligence · 年份：2024 · DOI：10.1609/aaai.v38i13.29352 · 被引用次数：48 · 研究领域：Computer Science

While shallow decision trees may be interpretable, larger ensemble models like gradient-boosted trees, which often set the state of the art in machine learning problems involving tabular data, still remain black box models. As a remedy, the Shapley value (SV) is a well-known concept in explainable artificial intelligence (XAI) research for quantifying additive feature attributions of predictions. The model-specific TreeSHAP methodology solves the exponential complexity for retrieving exact SVs from tree-based models. Expanding beyond individual feature attribution, Shapley interactions reveal the impact of intricate feature interactions of any order. In this work, we present TreeSHAP-IQ, an efficient method to compute any-order additive Shapley interactions for predictions of tree-based models. TreeSHAP-IQ is supported by a mathematical framework that exploits polynomial arithmetic to compute the interaction scores in a single recursive traversal of the tree, akin to Linear TreeSHAP. We apply TreeSHAP-IQ on state-of-the-art tree ensembles and explore interactions on well-established benchmark datasets.