Explaining Graph Neural Networks via Structure-aware Interaction Index

Fuente: arXiv
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Autori principali: Bui, Ngoc, Nguyen, Hieu Trung, Nguyen, Viet Anh, Ying, Rex
Natura: Preprint
Pubblicazione: 2024
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author Bui, Ngoc
Nguyen, Hieu Trung
Nguyen, Viet Anh
Ying, Rex
author_facet Bui, Ngoc
Nguyen, Hieu Trung
Nguyen, Viet Anh
Ying, Rex
contents The Shapley value is a prominent tool for interpreting black-box machine learning models thanks to its strong theoretical foundation. However, for models with structured inputs, such as graph neural networks, existing Shapley-based explainability approaches either focus solely on node-wise importance or neglect the graph structure when perturbing the input instance. This paper introduces the Myerson-Taylor interaction index that internalizes the graph structure into attributing the node values and the interaction values among nodes. Unlike the Shapley-based methods, the Myerson-Taylor index decomposes coalitions into components satisfying a pre-chosen connectivity criterion. We prove that the Myerson-Taylor index is the unique one that satisfies a system of five natural axioms accounting for graph structure and high-order interaction among nodes. Leveraging these properties, we propose Myerson-Taylor Structure-Aware Graph Explainer (MAGE), a novel explainer that uses the second-order Myerson-Taylor index to identify the most important motifs influencing the model prediction, both positively and negatively. Extensive experiments on various graph datasets and models demonstrate that our method consistently provides superior subgraph explanations compared to state-of-the-art methods.
format Preprint
id arxiv_https___arxiv_org_abs_2405_14352
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Explaining Graph Neural Networks via Structure-aware Interaction Index
Bui, Ngoc
Nguyen, Hieu Trung
Nguyen, Viet Anh
Ying, Rex
Machine Learning
The Shapley value is a prominent tool for interpreting black-box machine learning models thanks to its strong theoretical foundation. However, for models with structured inputs, such as graph neural networks, existing Shapley-based explainability approaches either focus solely on node-wise importance or neglect the graph structure when perturbing the input instance. This paper introduces the Myerson-Taylor interaction index that internalizes the graph structure into attributing the node values and the interaction values among nodes. Unlike the Shapley-based methods, the Myerson-Taylor index decomposes coalitions into components satisfying a pre-chosen connectivity criterion. We prove that the Myerson-Taylor index is the unique one that satisfies a system of five natural axioms accounting for graph structure and high-order interaction among nodes. Leveraging these properties, we propose Myerson-Taylor Structure-Aware Graph Explainer (MAGE), a novel explainer that uses the second-order Myerson-Taylor index to identify the most important motifs influencing the model prediction, both positively and negatively. Extensive experiments on various graph datasets and models demonstrate that our method consistently provides superior subgraph explanations compared to state-of-the-art methods.
title Explaining Graph Neural Networks via Structure-aware Interaction Index
topic Machine Learning
url https://arxiv.org/abs/2405.14352