Calibrating LLM-Based Evaluator
Yuxuan Liu Tianchi Yang Shaohan Huang Zihan Zhang Haizhen Huang Furu Wei Weiwei Deng Feng Sun Qi Zhang
Recent advancements in large language models (LLMs) on language modeling and
emergent capabilities make them a promising reference-free evaluator of natural
language generation quality, and a competent alternative to human evaluation.
However, hindered by the closed-source or high computational demand to host and
tune, there is a lack of practice to further calibrate an off-the-shelf
LLM-based evaluator towards better human alignment. In this work, we propose
AutoCalibrate, a multi-stage, gradient-free approach to automatically calibrate
and align an LLM-based evaluator toward human preference. Instead of explicitly
modeling human preferences, we first implicitly encompass them within a set of
human labels. Then, an initial set of scoring criteria is drafted by the
language model itself, leveraging in-context learning on different few-shot
examples. To further calibrate this set of criteria, we select the best
performers and re-draft them with self-refinement. Our experiments on multiple
text quality evaluation datasets illustrate a significant improvement in
correlation with expert evaluation through calibration. Our comprehensive
qualitative analysis conveys insightful intuitions and observations on the
essence of effective scoring criteria.