  We propose end-to-end multimodal fact-checking and explanation generation,
where the input is a claim and a large collection of web sources, including
articles, images, videos, and tweets, and the goal is to assess the
truthfulness of the claim by retrieving relevant evidence and predicting a
truthfulness label (e.g., support, refute or not enough information), and to
generate a statement to summarize and explain the reasoning and ruling process.
To support this research, we construct Mocheg, a large-scale dataset consisting
of 15,601 claims where each claim is annotated with a truthfulness label and a
ruling statement, and 33,880 textual paragraphs and 12,112 images in total as
evidence. To establish baseline performances on Mocheg, we experiment with
several state-of-the-art neural architectures on the three pipelined subtasks:
multimodal evidence retrieval, claim verification, and explanation generation,
and demonstrate that the performance of the state-of-the-art end-to-end
multimodal fact-checking does not provide satisfactory outcomes. To the best of
our knowledge, we are the first to build the benchmark dataset and solutions
for end-to-end multimodal fact-checking and explanation generation. The
dataset, source code and model checkpoints are available at
https://github.com/VT-NLP/Mocheg.

Computation and Language