通过用户聚类消除推荐中的用户固有偏好偏差,提升单槽推荐效果。
Breaker: Removing Shortcut Cues with User Clustering for Single-slot Recommendation System
- 利用用户表示聚类构建分组偏好模型,打破用户固有倾向的捷径依赖。
- 在美团平台实测中,点击率与转化率显著优于基线模型。
- 适合处理用户反馈有限、仅能单次展示的推荐场景,如本地生活服务。
在单槽推荐系统中,用户每次仅接触一个物品,系统无法同时收集多个物品的反馈,因此只能采用点对点建模,仅关注用户对单个物品的点击或转化概率,难以直接捕捉物品间的排序信息。由于用户侧信息远多于物品侧信息,模型易快速学习到与物品无关的用户内在倾向,形成捷径偏差,导致未能充分挖掘关键的用户-物品偏好关系。为此,本文提出Breaker模型,将用户表征聚类作为辅助任务,结合多塔结构实现基于聚类的偏好建模。通过聚类使每组内用户特征相似,提升了用户侧建模复杂度,迫使多塔结构通过聚类驱动参数学习更精准地建模用户-物品偏好,从而消除由用户内在倾向引发的捷径偏差。训练中引入延迟参数更新机制,增强训练稳定性与收敛性,支持辅助聚类与分类任务的端到端联合训练。离线与在线实验均表明,该方法超越现有基线,在美团平台已部署并日均服务数千万用户。
原文摘要 · Abstract (English)
In a single-slot recommendation system, users are only exposed to one item at a time, and the system cannot collect user feedback on multiple items simultaneously. Therefore, only pointwise modeling solutions can be adopted, focusing solely on modeling the likelihood of clicks or conversions for items by users to learn user-item preferences, without the ability to capture the ranking information among different items directly. However, since user-side information is often much more abundant than item-side information, the model can quickly learn the differences in user intrinsic tendencies, which are independent of the items they are exposed to. This can cause these intrinsic tendencies to become a shortcut bias for the model, leading to insufficient mining of the most concerned user-item preferences. To solve this challenge, we introduce the Breaker model. Breaker integrates an auxiliary task of user representation clustering with a multi-tower structure for cluster-specific preference modeling. By clustering user representations, we ensure that users within each cluster exhibit similar characteristics, which increases the complexity of the pointwise recommendation task on the user side. This forces the multi-tower structure with cluster-driven parameter learning to better model user-item preferences, ultimately eliminating shortcut biases related to user intrinsic tendencies. In terms of training, we propose a delayed parameter update mechanism to enhance training stability and convergence, enabling end-to-end joint training of the auxiliary clustering and classification tasks. Both offline and online experiments demonstrate that our method surpasses the baselines. It has already been deployed and is actively serving tens of millions of users daily on Meituan, one of the most popular e-commerce platforms for services.
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