ExplainabilityTransparencyAccountabilitycs.LG
Feature Importance for Time Series Data: Improving KernelSHAP
Mattia Villani, Joshua Lockhart, Daniele Magazzeni
October 5, 2022
arXiv.org
19 citations
Key Takeaways
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Shapley values provide mathematically rigorous explanations for time series predictions: The paper derives closed-form solutions for calculating SHAP values in time series models like VARMAX, offering a principled way to understand which past values and variables drive model predictions—moving beyond ad-hoc explanation methods.
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KernelSHAP can be adapted for time series, enabling practical explainability: The research demonstrates that KernelSHAP, a model-agnostic technique, works effectively on time series tasks, making it possible to explain predictions from any time series model without requiring access to internal model details.
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Feature importance explanations can detect meaningful events in time series data: By combining feature importance scores over time, the authors show that SHAP-based approaches can identify when significant events occur in sequential data—a practical application for domains like anomaly detection or financial market analysis.
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Time-consistent Shapley values address a unique challenge in sequential data: The paper explores "Time Consistent Shapley values," suggesting that standard Shapley approaches may not fully account for the temporal dependencies in time series, and proposes methods to address this limitation for more accurate explanations.
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These advances make complex time series models more interpretable for real-world deployment: By providing reliable explanation techniques for time series predictions, this work supports responsible AI practices by enabling practitioners to audit and validate model decisions in applications like forecasting and anomaly detection.