EviRerank: Adaptive Evidence Construction for Long-Document LLM Reranking

Minghan Li, Eric Gaussier, Juntao Li, Guodong Zhou


Abstract
Decoder-only LLM rerankers struggle with long documents: inference is costly and relevance signals can be diluted by irrelevant context. Motivated by an attention analysis indicating a consistent degradation trend when non-relevant text is appended, we propose EviRerank, an evidence-based long-document reranking framework for decoder-only LLMs. EviRerank (i) scores document blocks with a lightweight selector (BM25, bi-encoder, or cross-encoder), (ii) constructs a compact reranking context under a hard token cap by dynamically budgeting evidence blocks with Adaptive Evidence Budgeting (AEB) and adding a global summary cue via Summary Augmentation (SA), and (iii) reranks with a decoder-only LLM. Across TREC DL’19, DL’22, DL’23, and MLDR-zh, EviRerank consistently outperforms full-document LLM reranking and strong block-selection baselines while substantially reducing the required input length. On TREC DL’19, EviRerank reaches up to 0.744 nDCG@10 while substantially reducing reranking latency. Additional RankZephyr-7B experiments confirm transfer to listwise reranking under matched context budgets.
Anthology ID:
2026.findings-emnlp.704
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:
14772–14792
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.704/
DOI:
10.18653/2026.findings-emnlp.704
Bibkey:
Cite (ACL):
Minghan Li, Eric Gaussier, Juntao Li, and Guodong Zhou. 2026. EviRerank: Adaptive Evidence Construction for Long-Document LLM Reranking. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 14772–14792, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
EviRerank: Adaptive Evidence Construction for Long-Document LLM Reranking (Li et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.704.pdf