How Grounded is Wikipedia? A Study on Structured Evidential Support and Retrieval

TL;DR

This paper investigates Wikipedia's reliability by analyzing how well claims are supported by citations and introduces a new dataset to facilitate research on evidence retrieval and grounding in Wikipedia articles.

Contribution

It presents PeopleProfiles, a large-scale dataset of claim support annotations, and provides insights into citation support gaps and challenges in evidence retrieval.

Findings

22% of claims in lead sections are unsupported by the article body

30% of claims in the body lack support from accessible sources

Evidence retrieval remains challenging for recent rerankers

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: (1) ~22% of claims in Wikipedia lead sections are unsupported by the article body; (2) ~30% of claims in the article body are unsupported by their publicly accessible sources; and (3) 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.