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Main Authors: Xin, Haoran, Sun, Ying, Wang, Chao, Zhang, Weijia, Xiong, Hui
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.19464
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author Xin, Haoran
Sun, Ying
Wang, Chao
Zhang, Weijia
Xiong, Hui
author_facet Xin, Haoran
Sun, Ying
Wang, Chao
Zhang, Weijia
Xiong, Hui
contents Incorporating collaborative information (CI) effectively is crucial for leveraging LLMs in recommendation tasks. Existing approaches often encode CI using soft tokens or abstract identifiers, which introduces a semantic misalignment with the LLM's natural language pretraining and hampers knowledge integration. To address this, we propose expressing CI directly in natural language to better align with LLMs' semantic space. We achieve this by retrieving a curated set of the most relevant user behaviors in natural language form. However, identifying informative CI is challenging due to the complexity of similarity and utility assessment. To tackle this, we introduce a Self-assessing COllaborative REtrieval framework (SCORE) following the retrieve-rerank paradigm. First, a Collaborative Retriever (CAR) is developed to consider both collaborative patterns and semantic similarity. Then, a Self-assessing Reranker (SARE) leverages LLMs' own reasoning to assess and prioritize retrieved behaviors. Finally, the selected behaviors are prepended to the LLM prompt as natural-language CI to guide recommendation. Extensive experiments on two public datasets validate the effectiveness of SCORE in improving LLM-based recommendation.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19464
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle LLMs as Better Recommenders with Natural Language Collaborative Signals: A Self-Assessing Retrieval Approach
Xin, Haoran
Sun, Ying
Wang, Chao
Zhang, Weijia
Xiong, Hui
Information Retrieval
Incorporating collaborative information (CI) effectively is crucial for leveraging LLMs in recommendation tasks. Existing approaches often encode CI using soft tokens or abstract identifiers, which introduces a semantic misalignment with the LLM's natural language pretraining and hampers knowledge integration. To address this, we propose expressing CI directly in natural language to better align with LLMs' semantic space. We achieve this by retrieving a curated set of the most relevant user behaviors in natural language form. However, identifying informative CI is challenging due to the complexity of similarity and utility assessment. To tackle this, we introduce a Self-assessing COllaborative REtrieval framework (SCORE) following the retrieve-rerank paradigm. First, a Collaborative Retriever (CAR) is developed to consider both collaborative patterns and semantic similarity. Then, a Self-assessing Reranker (SARE) leverages LLMs' own reasoning to assess and prioritize retrieved behaviors. Finally, the selected behaviors are prepended to the LLM prompt as natural-language CI to guide recommendation. Extensive experiments on two public datasets validate the effectiveness of SCORE in improving LLM-based recommendation.
title LLMs as Better Recommenders with Natural Language Collaborative Signals: A Self-Assessing Retrieval Approach
topic Information Retrieval
url https://arxiv.org/abs/2505.19464