Enhancing Small Language Models in RAG via Triplet-Guided In-Context Distillation

Ilia Tambovtsev, Maria Molchanova, Anna Mikhailova, Alexey Korotkov, Ivan Sgibnev, Iurii Vizilter, Andrey Savchenko


Abstract
Retrieval-Augmented Generation (RAG) is widely used for knowledge-intensive question answering (QA) but typically relies on large language models (LLMs) as generators, which raises cost and privacy concerns. We propose TripletRAG, a simple, training-free method that converts LLM-teacher behavior into triplets (synthetic question, retrieved passages, reference answer), which are then provided as exemplar context to a small language model (SLM) at inference. TripletRAG requires only offline synthetic QA generation and retrieval; no SLM finetuning is needed. Across SQuAD and Natural Questions (KILT) datasets, triplet guidance substantially increases judge-based accuracy, and improves groundedness on SQuAD for models in the 1B–3B parameter range, with negligible or inconsistent gains for larger models (7B+). Compared to a strong lightweight baseline (MiniRAG), TripletRAG gives markedly better groundedness and correctness while keeping the pipeline simple and practical.
Anthology ID:
2026.groundlm-1.72
Volume:
Proceedings of the 1st Workshop on Grounding Language Models: Learning Faithfully and Efficiently (GroundLM 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Yimu Wang, Yee Man Choi, Di Wu, Siqi Ouyang, Mozhgan Nasr Azadani, Yi R. (May) Fung
Venues:
GroundLM | WS
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
1001–1015
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URL:
https://aclanthology.org/2026.groundlm-1.72/
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Cite (ACL):
Ilia Tambovtsev, Maria Molchanova, Anna Mikhailova, Alexey Korotkov, Ivan Sgibnev, Iurii Vizilter, and Andrey Savchenko. 2026. Enhancing Small Language Models in RAG via Triplet-Guided In-Context Distillation. In Proceedings of the 1st Workshop on Grounding Language Models: Learning Faithfully and Efficiently (GroundLM 2026), pages 1001–1015, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Enhancing Small Language Models in RAG via Triplet-Guided In-Context Distillation (Tambovtsev et al., GroundLM 2026)
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PDF:
https://aclanthology.org/2026.groundlm-1.72.pdf