MIG: Automatic Data Selection for Instruction Tuning by Maximizing
  Information Gain in Semantic Space
Authors: name: Yicheng Chen; name: Yining Li; name: Kai Hu; name: Zerun Ma; name: Haochen Ye; name: Kai Chen
Published: 2025-04-18 17:59:46

Abstract: Data quality and diversity are key to the construction of effective
instruction-tuning datasets. % With the increasing availability of open-source
instruction-tuning datasets, it is advantageous to automatically select
high-quality and diverse subsets from a vast amount of data. % Existing methods
typically prioritize instance quality and use heuristic rules to maintain
diversity. % However, this absence of a comprehensive view of the entire
collection often leads to suboptimal results. % Moreover, heuristic rules
generally focus on distance or clustering within the embedding space, which
fails to accurately capture the intent of complex instructions in the semantic
space. % To bridge this gap, we propose a unified method for quantifying the
information content of datasets. This method models the semantic space by
constructing a label graph and quantifies diversity based on the distribution
of information within the graph. % Based on such a measurement, we further
introduce an efficient sampling method that selects data samples iteratively to
Maximize the Information Gain (MIG) in semantic
space. % Experiments on various datasets and base models demonstrate that MIG
consistently outperforms state-of-the-art methods. % Notably, the model
fine-tuned with 5\% Tulu3 data sampled by MIG achieves comparable performance
to the official SFT model trained on the full dataset, with improvements of
+5.73\% on AlpacaEval and +6.89\% on Wildbench.