SPLADE-COVER: Coverage-Aware Representations for Learned Sparse Retrieval

Siddharth AK Singh, Eugene Yang, Dawn Lawrie, Trevor Adriaanse, Andrew Yates


Abstract
Long-form retrieval tasks such as report generation, multi-document summarization, and retrieval-augmented generation require systems to surface evidence covering multiple aspects (subtopics) of a complex query. Existing approaches to information coverage typically fall into two families: (1) methods such as Maximum Marginal Relevance (MMR) that rerank initial retrievals using document-similarity heuristics, and (2) expansion-based methods that invoke large language models at query time to produce subqueries, pseudo-answers, or expanded keywords. We propose SPLADE-COVER, a learned sparse retrieval model whose expansion mechanism is trained to be coverage-aware. SPLADE-COVER inherits the SPLADE-v3 architecture but is trained with an objective that distills multi-aspect subquery supervision into a single sparse representation, requiring no language-model invocation or reranking at query time. On benchmarks with nugget-level judgments, SPLADE-COVER often improves over its base model as measured by both information coverage metrics and relevance metrics, at a fraction of the query-time cost of generation-based methods.
Anthology ID:
2026.emnlp-main.2695
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:
61302–61312
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2695/
DOI:
Bibkey:
Cite (ACL):
Siddharth AK Singh, Eugene Yang, Dawn Lawrie, Trevor Adriaanse, and Andrew Yates. 2026. SPLADE-COVER: Coverage-Aware Representations for Learned Sparse Retrieval. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 61302–61312, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SPLADE-COVER: Coverage-Aware Representations for Learned Sparse Retrieval (Singh et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2695.pdf