Incorporating Attribution Importance for Improving Faithfulness Metrics

Fuente: arXiv
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Main Authors: Zhao, Zhixue, Aletras, Nikolaos
Format: Preprint
Published: 2023
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author Zhao, Zhixue
Aletras, Nikolaos
author_facet Zhao, Zhixue
Aletras, Nikolaos
contents Feature attribution methods (FAs) are popular approaches for providing insights into the model reasoning process of making predictions. The more faithful a FA is, the more accurately it reflects which parts of the input are more important for the prediction. Widely used faithfulness metrics, such as sufficiency and comprehensiveness use a hard erasure criterion, i.e. entirely removing or retaining the top most important tokens ranked by a given FA and observing the changes in predictive likelihood. However, this hard criterion ignores the importance of each individual token, treating them all equally for computing sufficiency and comprehensiveness. In this paper, we propose a simple yet effective soft erasure criterion. Instead of entirely removing or retaining tokens from the input, we randomly mask parts of the token vector representations proportionately to their FA importance. Extensive experiments across various natural language processing tasks and different FAs show that our soft-sufficiency and soft-comprehensiveness metrics consistently prefer more faithful explanations compared to hard sufficiency and comprehensiveness. Our code: https://github.com/casszhao/SoftFaith
format Preprint
id arxiv_https___arxiv_org_abs_2305_10496
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Incorporating Attribution Importance for Improving Faithfulness Metrics
Zhao, Zhixue
Aletras, Nikolaos
Computation and Language
Artificial Intelligence
Machine Learning
Feature attribution methods (FAs) are popular approaches for providing insights into the model reasoning process of making predictions. The more faithful a FA is, the more accurately it reflects which parts of the input are more important for the prediction. Widely used faithfulness metrics, such as sufficiency and comprehensiveness use a hard erasure criterion, i.e. entirely removing or retaining the top most important tokens ranked by a given FA and observing the changes in predictive likelihood. However, this hard criterion ignores the importance of each individual token, treating them all equally for computing sufficiency and comprehensiveness. In this paper, we propose a simple yet effective soft erasure criterion. Instead of entirely removing or retaining tokens from the input, we randomly mask parts of the token vector representations proportionately to their FA importance. Extensive experiments across various natural language processing tasks and different FAs show that our soft-sufficiency and soft-comprehensiveness metrics consistently prefer more faithful explanations compared to hard sufficiency and comprehensiveness. Our code: https://github.com/casszhao/SoftFaith
title Incorporating Attribution Importance for Improving Faithfulness Metrics
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2305.10496