Claim-Dissector: An Interpretable Fact-Checking System with Joint Re-ranking and Veracity Prediction

Martin Fajcik, Petr Motlicek, Pavel Smrz


Abstract
We present Claim-Dissector: a novel latent variable model for fact-checking and analysis, which given a claim and a set of retrieved evidence jointly learns to identify: (i) the relevant evidences to the given claim (ii) the veracity of the claim. We propose to disentangle the per-evidence relevance probability and its contribution to the final veracity probability in an interpretable way — the final veracity probability is proportional to a linear ensemble of per-evidence relevance probabilities. In this way, the individual contributions of evidences towards the final predicted probability can be identified. In per-evidence relevance probability, our model can further distinguish whether each relevant evidence is supporting (S) or refuting (R) the claim. This allows to quantify how much the S/R probability contributes to final verdict or to detect disagreeing evidence. Despite its interpretable nature, our system achieves results competetive with state-of-the-art on the FEVER dataset, as compared to typical two-stage system pipelines, while using significantly fewer parameters. Furthermore, our analysis shows that our model can learn fine-grained relevance cues while using coarse-grained supervision and we demonstrate it in 2 ways. (i) We show that our model can achieve competitive sentence recall while using only paragraph-level relevance supervision. (ii) Traversing towards the finest granularity of relevance, we show that our model is capable of identifying relevance at the token level. To do this, we present a new benchmark TLR-FEVER focusing on token-level interpretability — humans annotate tokens in relevant evidences they considered essential when making their judgment. Then we measure how similar are these annotations to the tokens our model is focusing on.
Anthology ID:
2023.findings-acl.647
Volume:
Findings of the Association for Computational Linguistics: ACL 2023
Month:
July
Year:
2023
Address:
Toronto, Canada
Editors:
Anna Rogers, Jordan Boyd-Graber, Naoaki Okazaki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
10184–10205
Language:
URL:
https://aclanthology.org/2023.findings-acl.647
DOI:
10.18653/v1/2023.findings-acl.647
Bibkey:
Cite (ACL):
Martin Fajcik, Petr Motlicek, and Pavel Smrz. 2023. Claim-Dissector: An Interpretable Fact-Checking System with Joint Re-ranking and Veracity Prediction. In Findings of the Association for Computational Linguistics: ACL 2023, pages 10184–10205, Toronto, Canada. Association for Computational Linguistics.
Cite (Informal):
Claim-Dissector: An Interpretable Fact-Checking System with Joint Re-ranking and Veracity Prediction (Fajcik et al., Findings 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.findings-acl.647.pdf
Video:
 https://aclanthology.org/2023.findings-acl.647.mp4