Retrieve Few, Verify Many: Segment-Level Evidence Reuse for Long-Form Factuality Assessment

Junjie Liao, Yuxia Wang


Abstract
Existing methods for evaluating the factuality of long-form LLM responses decompose text into atomic claims and verify each independently, retrieving evidence separately for every claim. This atom-independence assumption causes substantial retrieval redundancy, because adjacent claims in coherent text often draw from overlapping sources, a property we term semantic locality. We propose SegmentFact, a deterministic factuality assessor that partitions responses into semantic segments, extracts claims within each segment’s local context, and propagates retrieved evidence forward through a shared pool. Experiments on multiple benchmarks show that SegmentFact significantly reduces retrieval calls while maintaining accuracy comparable to existing detections.
Anthology ID:
2026.findings-emnlp.1584
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
33740–33753
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1584/
DOI:
Bibkey:
Cite (ACL):
Junjie Liao and Yuxia Wang. 2026. Retrieve Few, Verify Many: Segment-Level Evidence Reuse for Long-Form Factuality Assessment. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 33740–33753, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Retrieve Few, Verify Many: Segment-Level Evidence Reuse for Long-Form Factuality Assessment (Liao & Wang, Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1584.pdf