BiasRec: A General Bias-Aware Social Recommendation Model

The social recommendation aims to alleviate data sparsity problems and improve recommendation performance by incorporating user social data. And the recent popularity of graph neural networks (GNNs) has further advanced the development of social recommendation. However, most previous research erroneously assumed that user-item interaction data, such as ratings, directly reflects user preferences for items. In reality, various non-preference factors can also influence user ratings, referred to as biases in this paper. For example, users may still rate popular or high-quality items highly even if they are not interested in them, or some users may tend to give lower ratings to most items even if they like the item. Furthermore, existing research also lacks a general method for capturing and leveraging biases. To this end, we propose BiasRec, a bias-aware social recommendation model. BiasRec initially constructs a bias matrix for each user and item, calculates bias scores, and removes them from the raw rating data. Subsequently, the debiased data is fed into a GNN to learn users’ genuine preferences. Last, it reasonably combines biases and preferences to make predictions. We performed experiments on three real-world datasets and attained state-of-the-art results, showcasing the efficacy of our model.