@inproceedings{walden-etal-2026-grounded,
    title = "How Grounded is {W}ikipedia? A Study on Structured Evidential Support and Retrieval",
    author = "Walden, William Gantt  and
      Ricci, Kathryn  and
      Wanner, Miriam  and
      Jiang, Zhengping  and
      May, Chandler  and
      Zhou, Rongkun  and
      Van Durme, Benjamin",
    editor = "Liakata, Maria  and
      Moreira, Viviane P.  and
      Zhang, Jiajun  and
      Jurgens, David",
    booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {ACL} 2026",
    month = jul,
    year = "2026",
    address = "San Diego, California, United States",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-acl/2026.findings-acl.19/",
    pages = "400--420",
    ISBN = "979-8-89176-395-1",
    abstract = "Wikipedia is a critical resource for modern NLP, serving as a rich repository of up-to-date and citation-backed information on a wide variety of subjects. The reliability of Wikipedia{---}its groundedness in its cited sources{---}is vital to this purpose. This work analyzes both how grounded Wikipedia is and how readily fine-grained grounding evidence can be retrieved. To this end, we introduce PeopleProfiles{---}a large-scale, multi-level dataset of claim support annotations on biographical Wikipedia articles. We show that: {\textasciitilde}22{\%} of claims in Wikipedia *lead* sections are unsupported by the article body; {\textasciitilde}30{\%} of annotated claims in the article *body* are unsupported by their (publicly accessible) sources; and real-world Wikipedia citation practices often differ from documented standards. Finally, we show that complex evidence retrieval remains a challenge{---}even for recent reasoning rerankers."
}