UTDRM: unsupervised method for training debunked-narrative retrieval models

A key task in the fact-checking workflow is to establish whether the claim under investigation has already been debunked or fact-checked before. This is essentially a retrieval task where a misinformation claim is used as a query to retrieve from a corpus of debunks. Prior debunk retrieval methods have typically been trained on annotated pairs of misinformation claims and debunks. The novelty of this paper is an Unsupervised Method for Training Debunked-Narrative Retrieval Models (UTDRM) in a zero-shot setting, eliminating the need for human-annotated pairs. This approach leverages fact-checking articles for the generation of synthetic claims and employs a neural retrieval model for training. Our experiments show that UTDRM tends to match or exceed the performance of state-of-the-art methods on seven datasets, which demonstrates its effectiveness and broad applicability. The paper also analyses the impact of various factors on UTDRM’s performance, such as the quantity of fact-checking articles utilised, the number of synthetically generated claims employed, the proposed entity inoculation method, and the usage of large language models for retrieval.