SumRank: Aligning Summarization Models for Long-Document Listwise Reranking

Jincheng Feng, Wenhan Liu, Zhicheng Dou


Abstract
Large Language Models (LLMs) have demonstrated superior performance in listwise passage reranking task. However, directly applying them to rank long-form documents introduces both effectiveness and efficiency issues due to the substantially increased context length. To address this challenge, we propose a per-document summarization model SumRank, aligned with downstream listwise reranking, to compress long-form documents into concise rank-aligned summaries before the final listwise reranking stage. To develop our summarization model SumRank, we introduce a three-stage training pipeline consisting of cold-start Supervised Fine-Tuning (SFT), specialized Reinforcement Learning (RL) data construction, and rank-driven alignment via RL. This paradigm aligns the SumRank with downstream ranking objectives to preserve crucial relevance signals. We conduct extensive experiments on both in-domain (ID) benchmark datasets from the TREC Deep Learning tracks and out-of-domain (OOD) datasets from the BEIR benchmark. Results show that our lightweight SumRank model achieves state-of-the-art (SOTA) ranking performance while significantly improving efficiency by reducing both summarization overhead and reranking complexity.
Anthology ID:
2026.emnlp-main.1451
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
33129–33156
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1451/
DOI:
Bibkey:
Cite (ACL):
Jincheng Feng, Wenhan Liu, and Zhicheng Dou. 2026. SumRank: Aligning Summarization Models for Long-Document Listwise Reranking. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 33129–33156, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SumRank: Aligning Summarization Models for Long-Document Listwise Reranking (Feng et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1451.pdf