Knowledge Extraction on Semi-Structured Content: Does It Remain Relevant for Question Answering in the Era of LLMs?
Paper · 2026 · Kai Sun, Yin Huang, Srishti Mehra et al.
Summary
LLMs now answer questions over semi-structured web content (tables, attribute–value lists, free-form layouts) quite well. The authors ask whether extracting (subject, predicate, object) triples is still useful for QA. To find out, they extend the WebSRC benchmark in two ways. They add manually annotated triples for sampled cleaned pages, and they add a new set of raw, uncleaned webpages from popular Common Crawl domains that better reflect what a RAG system actually retrieves.
They then test commercial and open-source LLMs of different sizes on three things: extraction quality, QA with triple augmentation, and multi-task fine-tuning. They also try a cheaper option in which an LLM writes extraction scripts. Extraction is solid on cleaned pages but weak on whole pages. Even so, triples still raise QA accuracy, whether they are supplied at inference time or taught through multi-task training, and the two approaches add up. The benefit is largest for small models and noisy pages. This suggests knowledge extraction still has a place in LLM-based web QA.
Key points
- Dataset (released as SemiBench, non-commercial):
- Cleaned part: 180 pages from 60 WebSRC websites, 6,186 QA pairs, 4,741 triples.
- Whole-page part: 251 pages from 139 sites, 1,006 QA pairs, 30,263 triples (about 121 per page).
- Triple extraction (F1):
- LLMs reach about 77% on cleaned pages, versus 46% for the earlier GNN-based OpenIE method.
- On whole pages this falls to roughly 28%.
- QA accuracy:
- About 95% on cleaned pages but only 76% on whole pages.
- Adding ground-truth triples brings whole pages to 84%.
- Multi-task fine-tuning (QA plus extraction) reaches 83.5%.
- Combining both reaches about 87%.
- Script-based extraction:
- LLM-written scripts achieve 61% F1 on cleaned pages, comparable to fine-tuned Llama models (51% for 3B, 72% for 70B).
- The resulting triples give roughly a 5% QA gain over zero-shot.
- The approach has not yet worked on whole pages.
- Practical guidance:
- 70B-class models extract reasonably well with prompting alone; Trafilatura cleaning helps when pages are too long for the context window.
- 3B models are too weak for high-quality extraction.
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 works
🧭 Topics 2Research subjects and languages the work is about.Language models & pretraining · 3,320 worksQuestion answering · 441 works
Cite
Cite as Kai Sun, Yin Huang, Srishti Mehra, Mohammad Kachuee, Xilun Chen, Renjie Tao, Zhaojiang Lin, Andrea Jessee, Nirav Shah, Alex L Betty, Yue Liu, Anuj Kumar, Wen-tau Yih and Xin Luna Dong. 2026. Knowledge Extraction on Semi-Structured Content: Does It Remain Relevant for Question Answering in the Era of LLMs?. Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{sun2026knowledge,
title = {{Knowledge Extraction on Semi-Structured Content: Does It Remain Relevant for Question Answering in the Era of LLMs?}},
author = {Kai Sun, Yin Huang, Srishti Mehra, Mohammad Kachuee, Xilun Chen, Renjie Tao, Zhaojiang Lin, Andrea Jessee, Nirav Shah, Alex L Betty, Yue Liu, Anuj Kumar, Wen-tau Yih and Xin Luna Dong},
booktitle = {Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2026},
doi = {10.18653/v1/2026.eacl-long.91},
url = {https://doi.org/10.18653/v1/2026.eacl-long.91}
}References
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