Graph Representation Learning via Causal Diffusion for Out-of-Distribution Recommendation

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Hauptverfasser: Zhao, Chu, Yang, Enneng, Liang, Yuliang, Lan, Pengxiang, Liu, Yuting, Zhao, Jianzhe, Guo, Guibing, Wang, Xingwei
Format: Preprint
Veröffentlicht: 2024
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author Zhao, Chu
Yang, Enneng
Liang, Yuliang
Lan, Pengxiang
Liu, Yuting
Zhao, Jianzhe
Guo, Guibing
Wang, Xingwei
author_facet Zhao, Chu
Yang, Enneng
Liang, Yuliang
Lan, Pengxiang
Liu, Yuting
Zhao, Jianzhe
Guo, Guibing
Wang, Xingwei
contents Graph Neural Networks (GNNs)-based recommendation algorithms typically assume that training and testing data are drawn from independent and identically distributed (IID) spaces. However, this assumption often fails in the presence of out-of-distribution (OOD) data, resulting in significant performance degradation. In this study, we construct a Structural Causal Model (SCM) to analyze interaction data, revealing that environmental confounders (e.g., the COVID-19 pandemic) lead to unstable correlations in GNN-based models, thus impairing their generalization to OOD data. To address this issue, we propose a novel approach, graph representation learning via causal diffusion (CausalDiffRec) for OOD recommendation. This method enhances the model's generalization on OOD data by eliminating environmental confounding factors and learning invariant graph representations. Specifically, we use backdoor adjustment and variational inference to infer the real environmental distribution, thereby eliminating the impact of environmental confounders. This inferred distribution is then used as prior knowledge to guide the representation learning in the reverse phase of the diffusion process to learn the invariant representation. In addition, we provide a theoretical derivation that proves optimizing the objective function of CausalDiffRec can encourage the model to learn environment-invariant graph representations, thereby achieving excellent generalization performance in recommendations under distribution shifts. Our extensive experiments validate the effectiveness of CausalDiffRec in improving the generalization of OOD data, and the average improvement is up to 10.69% on Food, 18.83% on KuaiRec, 22.41% on Yelp2018, and 11.65% on Douban datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2408_00490
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Graph Representation Learning via Causal Diffusion for Out-of-Distribution Recommendation
Zhao, Chu
Yang, Enneng
Liang, Yuliang
Lan, Pengxiang
Liu, Yuting
Zhao, Jianzhe
Guo, Guibing
Wang, Xingwei
Machine Learning
Artificial Intelligence
Information Retrieval
Social and Information Networks
Graph Neural Networks (GNNs)-based recommendation algorithms typically assume that training and testing data are drawn from independent and identically distributed (IID) spaces. However, this assumption often fails in the presence of out-of-distribution (OOD) data, resulting in significant performance degradation. In this study, we construct a Structural Causal Model (SCM) to analyze interaction data, revealing that environmental confounders (e.g., the COVID-19 pandemic) lead to unstable correlations in GNN-based models, thus impairing their generalization to OOD data. To address this issue, we propose a novel approach, graph representation learning via causal diffusion (CausalDiffRec) for OOD recommendation. This method enhances the model's generalization on OOD data by eliminating environmental confounding factors and learning invariant graph representations. Specifically, we use backdoor adjustment and variational inference to infer the real environmental distribution, thereby eliminating the impact of environmental confounders. This inferred distribution is then used as prior knowledge to guide the representation learning in the reverse phase of the diffusion process to learn the invariant representation. In addition, we provide a theoretical derivation that proves optimizing the objective function of CausalDiffRec can encourage the model to learn environment-invariant graph representations, thereby achieving excellent generalization performance in recommendations under distribution shifts. Our extensive experiments validate the effectiveness of CausalDiffRec in improving the generalization of OOD data, and the average improvement is up to 10.69% on Food, 18.83% on KuaiRec, 22.41% on Yelp2018, and 11.65% on Douban datasets.
title Graph Representation Learning via Causal Diffusion for Out-of-Distribution Recommendation
topic Machine Learning
Artificial Intelligence
Information Retrieval
Social and Information Networks
url https://arxiv.org/abs/2408.00490