ProMax: Exploring the Potential of LLM-derived Profiles with Distribution Shaping for Recommender Systems

TL;DR

ProMax leverages distribution shaping and dense retrieval to enhance recommender systems by better utilizing LLM-derived user profiles, significantly improving performance across multiple datasets.

Contribution

This paper introduces a novel distribution shaping framework for recommender systems that effectively exploits LLM-derived profiles through retrieval and distribution guidance.

Findings

ProMax improves baseline recommendation models on four datasets.

ProMax outperforms existing LLM-based recommendation approaches.

Distribution shaping guides models to learn preferences for unseen items.

Abstract

The remarkable text understanding and generation capabilities of large language models (LLMs) have revitalized the field of general recommendation based on implicit user feedback. Rather than deploying LLMs directly as recommendation models, a more flexible paradigm leverages their ability to interpret users' historical interactions and semantic contexts to extract structured profiles that characterize user preferences. These profiles can be further transformed into actionable high-dimensional representations, serving as powerful signals to augment and strengthen recommendation models. However, the mechanism by which such profiles enhance recommendation performance within the feature space remains insufficiently understood. Moreover, existing studies predominantly rely on nonlinear alignment and fusion strategies to incorporate these profiles, which often lead to semantic loss and fail to fully exploit their potential. To address these limitations, we revisit profiles from a retrieval perspective and propose a simple yet effective recommendation framework built upon distribution shaping (ProMax) in this paper. We begin by employing dense retrieval to uncover the collaborative relationships between user and item profiles within the feature space. Based on this insight, we introduce a dual distribution-reshaping process, in which the profile distribution acts as a guiding signal to steer the recommendation model toward learning user preferences for unseen items beyond the scope of observed interactions. We apply ProMax to four classic recommendation methods on three public datasets. The results indicate that ProMax substantially improves base model performance and outperforms existing LLM-based recommendation approaches.