Mosaic-IT: Cost-Free Compositional Data Synthesis for Instruction Tuning

Ming Li, Pei Chen, Chenguang Wang, Hongyu Zhao, Yijun Liang, YuPeng Hou, Fuxiao Liu, Tianyi Zhou


Abstract
Finetuning large language models with a variety of instruction-response pairs has enhanced their capability to understand and follow instructions. Current instruction tuning primarily relies on teacher models or human intervention to generate and refine the instructions and responses for training, which are costly, non-sustainable, and may lack diversity. In this paper, we introduce Mosaic Instruction Tuning (Mosaic-IT), a human/model-free compositional data synthesis method that can efficiently create rich and diverse augmentations from existing instruction tuning data to enhance the LLMs. Mosaic-IT randomly concatenates multiple instruction data into one and trains the model to produce the corresponding responses with predefined higher-level meta-instructions to strengthen its multi-step instruction-following and format-following skills. Our extensive evaluations demonstrate a superior performance and training efficiency of Mosaic-IT, which achieves consistent performance improvements over various benchmarks and an 80% reduction in training costs compared with original instruction tuning.
Anthology ID:
2025.findings-acl.1297
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venues:
Findings | WS
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Publisher:
Association for Computational Linguistics
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Pages:
25287–25318
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URL:
https://preview.aclanthology.org/acl25-workshop-ingestion/2025.findings-acl.1297/
DOI:
Bibkey:
Cite (ACL):
Ming Li, Pei Chen, Chenguang Wang, Hongyu Zhao, Yijun Liang, YuPeng Hou, Fuxiao Liu, and Tianyi Zhou. 2025. Mosaic-IT: Cost-Free Compositional Data Synthesis for Instruction Tuning. In Findings of the Association for Computational Linguistics: ACL 2025, pages 25287–25318, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Mosaic-IT: Cost-Free Compositional Data Synthesis for Instruction Tuning (Li et al., Findings 2025)
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https://preview.aclanthology.org/acl25-workshop-ingestion/2025.findings-acl.1297.pdf