Cross-document Misinformation Detection based on Event Graph Reasoning

For emerging events, human readers are often exposed to both real news and fake news.Multiple news articles may contain complementary or contradictory information that readers can leverage to help detect fake news.Inspired by this process, we propose a novel task of cross-document misinformation detection.Given a cluster of topically related news documents, we aim to detect misinformation at both document level and a more finegrained level, event level.Due to the lack of data, we generate fake news by manipulating real news, and construct 3 new datasets with 422, 276, and 1, 413 clusters of topically related documents, respectively.We further propose a graph-based detector that constructs a cross-document knowledge graph using cross-document event coreference resolution and employs a heterogeneous graph neural network to conduct detection at two levels.We then feed the event-level detection results into the document-level detector.Experimental results show that our proposed method significantly outperforms existing methods by up to 7 F1 points on this new task. 1