Abstract:Implicit feedback data plays a crucial role in recommender systems, but it often suffers from sparsity and biases, including exposure bias and conformity bias. Existing debiasing methods tend to address only one type of bias, which can impact personalized recommendation effectiveness, or require a expensive debiased dataset as auxiliary information for multiple debiasing. To address this issue, a collaborative filtering recommendation algorithm specifically designed for sparse implicit feedback data, which can simultaneously debias exposure bias and conformity bias, is proposed. The algorithm utilizes the proposed dual inverse propensity weighting method and a contrastive learning auxiliary task to remove the two biases contained in the implicit feedback data which are input into dual-tower autoencoders so that the complete algorithm can estimate users’ preference probability to items. Experimental results demonstrate that the proposed algorithm outperforms comparative algorithms in terms of normalized discounted cumulative gain (NDCG@K), mean average precision (MAP@K), and recall (Recall@K) on publicly available debiased datasets such as Coat and Yahoo!R3.