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Main Authors: Kiyohara, Haruka, Narita, Yusuke, Saito, Yuta, Tateno, Kei, Udagawa, Takuma
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2510.07635
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author Kiyohara, Haruka
Narita, Yusuke
Saito, Yuta
Tateno, Kei
Udagawa, Takuma
author_facet Kiyohara, Haruka
Narita, Yusuke
Saito, Yuta
Tateno, Kei
Udagawa, Takuma
contents In many real recommender systems, novel items are added frequently over time. The importance of sufficiently presenting novel actions has widely been acknowledged for improving long-term user engagement. A recent work builds on Off-Policy Learning (OPL), which trains a policy from only logged data, however, the existing methods can be unsafe in the presence of novel actions. Our goal is to develop a framework to enforce exploration of novel actions with a guarantee for safety. To this end, we first develop Safe Off-Policy Policy Gradient (Safe OPG), which is a model-free safe OPL method based on a high confidence off-policy evaluation. In our first experiment, we observe that Safe OPG almost always satisfies a safety requirement, even when existing methods violate it greatly. However, the result also reveals that Safe OPG tends to be too conservative, suggesting a difficult tradeoff between guaranteeing safety and exploring novel actions. To overcome this tradeoff, we also propose a novel framework called Deployment-Efficient Policy Learning for Safe User Exploration, which leverages safety margin and gradually relaxes safety regularization during multiple (not many) deployments. Our framework thus enables exploration of novel actions while guaranteeing safe implementation of recommender systems.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07635
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Safely Exploring Novel Actions in Recommender Systems via Deployment-Efficient Policy Learning
Kiyohara, Haruka
Narita, Yusuke
Saito, Yuta
Tateno, Kei
Udagawa, Takuma
Artificial Intelligence
In many real recommender systems, novel items are added frequently over time. The importance of sufficiently presenting novel actions has widely been acknowledged for improving long-term user engagement. A recent work builds on Off-Policy Learning (OPL), which trains a policy from only logged data, however, the existing methods can be unsafe in the presence of novel actions. Our goal is to develop a framework to enforce exploration of novel actions with a guarantee for safety. To this end, we first develop Safe Off-Policy Policy Gradient (Safe OPG), which is a model-free safe OPL method based on a high confidence off-policy evaluation. In our first experiment, we observe that Safe OPG almost always satisfies a safety requirement, even when existing methods violate it greatly. However, the result also reveals that Safe OPG tends to be too conservative, suggesting a difficult tradeoff between guaranteeing safety and exploring novel actions. To overcome this tradeoff, we also propose a novel framework called Deployment-Efficient Policy Learning for Safe User Exploration, which leverages safety margin and gradually relaxes safety regularization during multiple (not many) deployments. Our framework thus enables exploration of novel actions while guaranteeing safe implementation of recommender systems.
title Safely Exploring Novel Actions in Recommender Systems via Deployment-Efficient Policy Learning
topic Artificial Intelligence
url https://arxiv.org/abs/2510.07635