Quantification of Large Language Model Distillation
Sunbowen Lee, Junting Zhou, Chang Ao, Kaige Li, Xinrun Du, Sirui He, Haihong Wu, Tianci Liu, Jiaheng Liu, Hamid Alinejad-Rokny, Min Yang, Yitao Liang, Zhoufutu Wen, Shiwen Ni
TL;DR
The paper addresses the problem of quantifying large language model distillation and its tendency to homogenize model behavior. It introduces two metrics, Identity Consistency Evaluation (ICE) and Response Similarity Evaluation (RSE), to quantify identity leakage and cross-model response similarity, respectively, and pairs them with a jailbreak-based framework (GPTFuzz) to reveal distillation-driven vulnerabilities. Empirical results show that many well-known LLMs exhibit high distillation levels, with base models typically distilling more than aligned ones, while exceptions like Claude, Doubao, and Gemini demonstrate lower levels. The study emphasizes transparency in training and distillation data, highlighting implications for robustness and safety, and proposes a systematic approach for evaluating distillation that can inform independent development and policy. Overall, ICE and RSE provide a practical, interpretable framework to measure distillation effects, guiding future improvements in model transparency and diversity.
Abstract
Model distillation is a fundamental technique in building large language models (LLMs), transferring knowledge from a teacher model to a student model. However, distillation can lead to model homogenization, reducing diversity among models and impairing their ability to robustly handle complex or novel tasks. These limitations underscore the need to systematically quantify the distillation process and its impact. In this work, we propose a framework to evaluate and quantify model distillation. Our method addresses two key aspects: (1) Identifying identity cognition contradictions to assess discrepancies in how models perceive and represent identity-related information, and (2) Analyzing multi-granularity response similarities across models to measure the extent of homogenization. Experimental results demonstrate two key insights: (1) Well-known closed-source and open-source LLMs usually exhibit high distillation degrees, except for Claude, Doubao, and Gemini. (2) Base LLMs show higher distillation degrees compared to aligned LLMs. By offering a systematic approach to improve the transparency of LLM data distillation, we call for LLMs with more independent development and more transparent technical reports to improve LLMs' robustness and safety. The code and data are available under https://github.com/Aegis1863/LLMs-Distillation-Quantification.
