Querit-Reranker: Training Compact Multilingual Rerankers via Efficient Label-Free Distribution Adaptation

Yunfei Zhong, Jun Yang, Wei Huang, Yinqiong Cai, Haosheng Qian, Yixing Fan, Ruqing Zhang, Lixin Su, Daiting Shi, Jiafeng Guo


Abstract
A deployable multilingual reranker must not only generalize across languages, domains, and ranking tasks, but also remain efficient to serve as a second-stage reranker in practical systems. However, adapting it to new target distributions typically requires extensive task-specific relevance annotations. We present Querit-Reranker, a family of multilingual rerankers trained with a data-centric pipeline for label-efficient adaptation. We instantiate it as Querit-Reranker-A0.4B, initialized from an in-house MoE backbone with 0.4B activated parameters, and Querit-Reranker-4B, initialized from Qwen3-Embedding-4B. Our pipeline first learns general relevance modeling from large-scale ranking-oriented data, then adapts to target distributions through synthetic-query mining with teacher scores as continuous soft labels. To consolidate complementary task-adapted strengths, we further merge checkpoints via spherical linear interpolation, obtaining a single deployable model without runtime ensembling overhead. Using Qwen3-Embedding-0.6B as the first-stage retriever, Querit-Reranker-A0.4B improves average nDCG@10 from 54.11 to 59.28 on BEIR and from 59.87 to 67.70 on MIRACL. On MTEB Multilingual v2 Reranking, it also shows competitive performance with larger embedding-based models, while Querit-Reranker-4B further achieves state-of-the-art performance among all evaluated models. We release both models on Hugging Face.
Anthology ID:
2026.emnlp-industry.97
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
1648–1662
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.97/
DOI:
Bibkey:
Cite (ACL):
Yunfei Zhong, Jun Yang, Wei Huang, Yinqiong Cai, Haosheng Qian, Yixing Fan, Ruqing Zhang, Lixin Su, Daiting Shi, and Jiafeng Guo. 2026. Querit-Reranker: Training Compact Multilingual Rerankers via Efficient Label-Free Distribution Adaptation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 1648–1662, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Querit-Reranker: Training Compact Multilingual Rerankers via Efficient Label-Free Distribution Adaptation (Zhong et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.97.pdf