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Main Authors: Baer, Gregor, Grau, Isel, Zhang, Chao, Van Gorp, Pieter
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2502.17022
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author Baer, Gregor
Grau, Isel
Zhang, Chao
Van Gorp, Pieter
author_facet Baer, Gregor
Grau, Isel
Zhang, Chao
Van Gorp, Pieter
contents As machine learning models become increasingly prevalent in time series applications, Explainable Artificial Intelligence (XAI) methods are essential for understanding their predictions. Within XAI, feature attribution methods aim to identify which input features contribute the most to a model's prediction, with their evaluation typically relying on perturbation-based metrics. Through systematic empirical analysis across multiple datasets, model architectures, and perturbation strategies, we reveal previously overlooked class-dependent effects in these metrics: they show varying effectiveness across classes, achieving strong results for some while remaining less sensitive to others. In particular, we find that the most effective perturbation strategies often demonstrate the most pronounced class differences. Our analysis suggests that these effects arise from the learned biases of classifiers, indicating that perturbation-based evaluation may reflect specific model behaviors rather than intrinsic attribution quality. We propose an evaluation framework with a class-aware penalty term to help assess and account for these effects in evaluating feature attributions, offering particular value for class-imbalanced datasets. Although our analysis focuses on time series classification, these class-dependent effects likely extend to other structured data domains where perturbation-based evaluation is common.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17022
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Class-Dependent Perturbation Effects in Evaluating Time Series Attributions
Baer, Gregor
Grau, Isel
Zhang, Chao
Van Gorp, Pieter
Machine Learning
Artificial Intelligence
As machine learning models become increasingly prevalent in time series applications, Explainable Artificial Intelligence (XAI) methods are essential for understanding their predictions. Within XAI, feature attribution methods aim to identify which input features contribute the most to a model's prediction, with their evaluation typically relying on perturbation-based metrics. Through systematic empirical analysis across multiple datasets, model architectures, and perturbation strategies, we reveal previously overlooked class-dependent effects in these metrics: they show varying effectiveness across classes, achieving strong results for some while remaining less sensitive to others. In particular, we find that the most effective perturbation strategies often demonstrate the most pronounced class differences. Our analysis suggests that these effects arise from the learned biases of classifiers, indicating that perturbation-based evaluation may reflect specific model behaviors rather than intrinsic attribution quality. We propose an evaluation framework with a class-aware penalty term to help assess and account for these effects in evaluating feature attributions, offering particular value for class-imbalanced datasets. Although our analysis focuses on time series classification, these class-dependent effects likely extend to other structured data domains where perturbation-based evaluation is common.
title Class-Dependent Perturbation Effects in Evaluating Time Series Attributions
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2502.17022