通过优化表示分布缓解推荐偏差,提升冷门商品和沉默用户推荐效果。
Mitigating Recommendation Biases via Group-Alignment and Global-Uniformity in Representation Learning
- 从表示分布角度设计分组对齐与全局均匀性正则化
- 在三个真实数据集上显著降低热门商品偏好,提升长尾商品推荐率
- 适用于主流推荐模型,尤其适合改善冷启动和低活跃用户体验
协同过滤(CF)在现代推荐系统中至关重要,但训练数据不平衡常导致推荐偏差,使模型过度偏好热门商品并忽略不活跃用户。现有方法通过重采样、重排序或增强鲁棒性来缓解,但可能影响精度或依赖敏感权重策略。本文深入分析偏差成因,提出基于表示分布的去偏框架AURL,识别出用户与物品表示中的两类问题:分组差异(group-discrepancy)与全局坍缩(global-collapse)。为此,设计两种正则化项:分组对齐(group-alignment)使长尾实体表示趋近热门实体,全局均匀性(global-uniformity)通过均匀分布保持信息。在三个真实数据集及多种推荐基线模型上的实验验证了该方法的有效性,显著降低了推荐偏差。
原文摘要 · Abstract (English)
Collaborative Filtering~(CF) plays a crucial role in modern recommender systems, leveraging historical user-item interactions to provide personalized suggestions. However, CF-based methods often encounter biases due to imbalances in training data. This phenomenon makes CF-based methods tend to prioritize recommending popular items and performing unsatisfactorily on inactive users. Existing works address this issue by rebalancing training samples, reranking recommendation results, or making the modeling process robust to the bias. Despite their effectiveness, these approaches can compromise accuracy or be sensitive to weighting strategies, making them challenging to train. In this paper, we deeply analyze the causes and effects of the biases and propose a framework to alleviate biases in recommendation from the perspective of representation distribution, namely Group-Alignment and Global-Uniformity Enhanced Representation Learning for Debiasing Recommendation (AURL). Specifically, we identify two significant problems in the representation distribution of users and items, namely group-discrepancy and global-collapse. These two problems directly lead to biases in the recommendation results. To this end, we propose two simple but effective regularizers in the representation space, respectively named group-alignment and global-uniformity. The goal of group-alignment is to bring the representation distribution of long-tail entities closer to that of popular entities, while global-uniformity aims to preserve the information of entities as much as possible by evenly distributing representations. Our method directly optimizes both the group-alignment and global-uniformity regularization terms to mitigate recommendation biases. Extensive experiments on three real datasets and various recommendation backbones verify the superiority of our proposed framework.
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