MAVEN-Fact: A Large-scale Event Factuality Detection Dataset
Chunyang Li, Hao Peng, Xiaozhi Wang, Yunjia Qi, Lei Hou, Bin Xu, Juanzi Li
TL;DR
MAVEN-Fact introduces the largest large-scale Event Factuality Detection dataset, annotating 112,276 events with five factuality classes and supporting evidence, built on the MAVEN framework to include event types, arguments, and relations. The paper presents an LLM-then-Human annotation workflow to reduce labeling costs while maintaining high data quality, and provides rich annotations to support analyses of event elements and hallucination mitigation. Experimental results show MAVEN-Fact is challenging for both fine-tuned EFD models and LLMs, though incorporating event arguments and relations helps fine-tuned models, while prompting strategies partially improve LLM performance. A preliminary application demonstrates that explicitly injecting factuality information can mitigate event-related hallucinations in LLMs. The dataset and code are released to advance faithful event understanding research and applications.
Abstract
Event Factuality Detection (EFD) task determines the factuality of textual events, i.e., classifying whether an event is a fact, possibility, or impossibility, which is essential for faithfully understanding and utilizing event knowledge. However, due to the lack of high-quality large-scale data, event factuality detection is under-explored in event understanding research, which limits the development of EFD community. To address these issues and provide faithful event understanding, we introduce MAVEN-Fact, a large-scale and high-quality EFD dataset based on the MAVEN dataset. MAVEN-Fact includes factuality annotations of 112,276 events, making it the largest EFD dataset. Extensive experiments demonstrate that MAVEN-Fact is challenging for both conventional fine-tuned models and large language models (LLMs). Thanks to the comprehensive annotations of event arguments and relations in MAVEN, MAVEN-Fact also supports some further analyses and we find that adopting event arguments and relations helps in event factuality detection for fine-tuned models but does not benefit LLMs. Furthermore, we preliminarily study an application case of event factuality detection and find it helps in mitigating event-related hallucination in LLMs. Our dataset and codes can be obtained from \url{https://github.com/lcy2723/MAVEN-FACT}
