Changxuan Sun
2025
FaStFact: Faster, Stronger Long-Form Factuality Evaluations in LLMs
Yingjia Wan
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Haochen Tan
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Xiao Zhu
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Xinyu Zhou
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Zhiwei Li
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Qingsong Lv
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Changxuan Sun
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Jiaqi Zeng
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Yi Xu
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Jianqiao Lu
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Yinhong Liu
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Zhijiang Guo
Findings of the Association for Computational Linguistics: EMNLP 2025
Evaluating the factuality of long-form generations from Large Language Models (LLMs) remains challenging due to accuracy issues and costly human assessment. Prior evaluation pipelines attempt this by decomposing text into claims, searching for evidence, and verifying claims, but suffer from critical drawbacks: (1) inefficiency due to complex pipeline components unsuitable for long LLM outputs, and (2) ineffectiveness stemming from inaccurate claim sets and insufficient evidence collection of one-line SERP snippets. To address these limitations, we adapt the existing decompose-then-verify evaluation framework and propose **FaStFact**, a fast and strong evaluation pipeline that achieves the highest alignment with human evaluation and efficiency among existing baselines. FaStFact first employs chunk-level claim extraction integrated with confidence-based pre-verification, significantly reducing the cost of web searching and inference calling while ensuring reliability. For searching and verification, it gathers document-level evidence from crawled website pages for retrieval during verification, addressing the evidence insufficiency problem in previous pipelines. Extensive experiments based on an aggregated and manually annotated benchmark demonstrate the reliability of FaStFact in both efficiently and effectively evaluating the factuality of long-form LLM generations. We submit the paper with code and benchmark, and will make them publicly available to facilitate research.
2024
Two Issues with Chinese Spelling Correction and A Refinement Solution
Changxuan Sun
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Linlin She
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Xuesong Lu
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
The Chinese Spelling Correction (CSC) task aims to detect and correct misspelled characters in Chinese text, and has received lots of attention in the past few years. Most recent studies adopt a Transformer-based model and leverage different features of characters such as pronunciation, glyph and contextual information to enhance the model’s ability to complete the task. Despite their state-of-the-art performance, we observe two issues that should be addressed to further advance the CSC task. First, the widely-used benchmark datasets SIGHAN13, SIGHAN14 and SIGHAN15, contain many mistakes. Hence the performance of existing models is not accurate and should be re-evaluated. Second, existing models seem to have reached a performance bottleneck, where the improvements on the SIGHAN’s testing sets are increasingly smaller and unstable. To deal with the two issues, we make two contributions: (1) we manually fix the SIGHAN datasets and re-evaluate four representative CSC models using the fixed datasets; (2) we analyze the new results to identify the spelling errors that none of the four models successfully corrects, based on which we propose a simple yet effective refinement solution. Experimental results show that our solution improves the four models in all metrics by notable margins.
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- Zhijiang Guo 1
- Zhiwei Li 1
- Yinhong Liu 1
- Xuesong Lu 1
- Jianqiao Lu 1
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