Proxy-Based Approximation of Shapley and Banzhaf Interactions

Fuente: arXiv
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Main Authors: Thies, Santo M. A. R., Baniecki, Hubert, Witter, R. Teal, Hüllermeier, Eyke, Muschalik, Maximilian, Fumagalli, Fabian
Format: Preprint
Published: 2026
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author Thies, Santo M. A. R.
Baniecki, Hubert
Witter, R. Teal
Hüllermeier, Eyke
Muschalik, Maximilian
Fumagalli, Fabian
author_facet Thies, Santo M. A. R.
Baniecki, Hubert
Witter, R. Teal
Hüllermeier, Eyke
Muschalik, Maximilian
Fumagalli, Fabian
contents Shapley and Banzhaf interactions capture the complex dynamics inherent in modern machine learning applications. However, current estimators for these higher-order interactions trade off between speed and accuracy. To overcome this limitation, we introduce ProxySHAP. ProxySHAP reconciles the high sample efficiency of tree-based proxy models with a principled path to consistency via residual correction. On a theoretical level, we derive a polynomial-time generalization of interventional TreeSHAP to compute exact interaction indices for tree ensembles, successfully bypassing exponential tree-depth dependencies in prior methods. Furthermore, we formally analyze the residual adjustment strategy, characterizing the specific conditions under which Maximum Sample Reuse (MSR) corrects proxy bias without its variance scaling exponentially with interaction size. Extensive benchmarking demonstrates that ProxySHAP sets a new state-of-the-art standard for approximation quality, including in large-scale applications with thousands of features. By achieving the lowest error in both small- and large-budget regimes, ProxySHAP significantly outperforms the prior best estimators ProxySPEX and KernelSHAP-IQ, while also delivering superior performance on downstream explainability tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_22738
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Proxy-Based Approximation of Shapley and Banzhaf Interactions
Thies, Santo M. A. R.
Baniecki, Hubert
Witter, R. Teal
Hüllermeier, Eyke
Muschalik, Maximilian
Fumagalli, Fabian
Machine Learning
Artificial Intelligence
Shapley and Banzhaf interactions capture the complex dynamics inherent in modern machine learning applications. However, current estimators for these higher-order interactions trade off between speed and accuracy. To overcome this limitation, we introduce ProxySHAP. ProxySHAP reconciles the high sample efficiency of tree-based proxy models with a principled path to consistency via residual correction. On a theoretical level, we derive a polynomial-time generalization of interventional TreeSHAP to compute exact interaction indices for tree ensembles, successfully bypassing exponential tree-depth dependencies in prior methods. Furthermore, we formally analyze the residual adjustment strategy, characterizing the specific conditions under which Maximum Sample Reuse (MSR) corrects proxy bias without its variance scaling exponentially with interaction size. Extensive benchmarking demonstrates that ProxySHAP sets a new state-of-the-art standard for approximation quality, including in large-scale applications with thousands of features. By achieving the lowest error in both small- and large-budget regimes, ProxySHAP significantly outperforms the prior best estimators ProxySPEX and KernelSHAP-IQ, while also delivering superior performance on downstream explainability tasks.
title Proxy-Based Approximation of Shapley and Banzhaf Interactions
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2605.22738