Unified PAC-Bayesian Study of Pessimism for Offline Policy Learning with Regularized Importance Sampling

Fuente: arXiv
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Auteurs principaux: Aouali, Imad, Brunel, Victor-Emmanuel, Rohde, David, Korba, Anna
Format: Preprint
Publié: 2024
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author Aouali, Imad
Brunel, Victor-Emmanuel
Rohde, David
Korba, Anna
author_facet Aouali, Imad
Brunel, Victor-Emmanuel
Rohde, David
Korba, Anna
contents Off-policy learning (OPL) often involves minimizing a risk estimator based on importance weighting to correct bias from the logging policy used to collect data. However, this method can produce an estimator with a high variance. A common solution is to regularize the importance weights and learn the policy by minimizing an estimator with penalties derived from generalization bounds specific to the estimator. This approach, known as pessimism, has gained recent attention but lacks a unified framework for analysis. To address this gap, we introduce a comprehensive PAC-Bayesian framework to examine pessimism with regularized importance weighting. We derive a tractable PAC-Bayesian generalization bound that universally applies to common importance weight regularizations, enabling their comparison within a single framework. Our empirical results challenge common understanding, demonstrating the effectiveness of standard IW regularization techniques.
format Preprint
id arxiv_https___arxiv_org_abs_2406_03434
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unified PAC-Bayesian Study of Pessimism for Offline Policy Learning with Regularized Importance Sampling
Aouali, Imad
Brunel, Victor-Emmanuel
Rohde, David
Korba, Anna
Machine Learning
Artificial Intelligence
Off-policy learning (OPL) often involves minimizing a risk estimator based on importance weighting to correct bias from the logging policy used to collect data. However, this method can produce an estimator with a high variance. A common solution is to regularize the importance weights and learn the policy by minimizing an estimator with penalties derived from generalization bounds specific to the estimator. This approach, known as pessimism, has gained recent attention but lacks a unified framework for analysis. To address this gap, we introduce a comprehensive PAC-Bayesian framework to examine pessimism with regularized importance weighting. We derive a tractable PAC-Bayesian generalization bound that universally applies to common importance weight regularizations, enabling their comparison within a single framework. Our empirical results challenge common understanding, demonstrating the effectiveness of standard IW regularization techniques.
title Unified PAC-Bayesian Study of Pessimism for Offline Policy Learning with Regularized Importance Sampling
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2406.03434