Fine-tuning Done Right in Model Editing
Authors: name: Wanli Yang; name: Fei Sun; name: Rui Tang; name: Hongyu Zang; name: Du Su; name: Qi Cao; name: Jingang Wang; name: Huawei Shen; name: Xueqi Cheng
Published: 2025-09-26 08:53:13

Abstract: Fine-tuning, a foundational method for adapting large language models, has
long been considered ineffective for model editing. Here, we challenge this
belief, arguing that the reported failure arises not from the inherent
limitation of fine-tuning itself, but from adapting it to the sequential nature
of the editing task, a single-pass depth-first pipeline that optimizes each
sample to convergence before moving on. While intuitive, this depth-first
pipeline coupled with sample-wise updating over-optimizes each edit and induces
interference across edits. Our controlled experiments reveal that simply
restoring fine-tuning to the standard breadth-first (i.e., epoch-based)
pipeline with mini-batch optimization substantially improves its effectiveness
for model editing. Moreover, fine-tuning in editing also suffers from
suboptimal tuning parameter locations inherited from prior methods. Through
systematic analysis of tuning locations, we derive LocFT-BF, a simple and
effective localized editing method built on the restored fine-tuning framework.
Extensive experiments across diverse LLMs and datasets demonstrate that
LocFT-BF outperforms state-of-the-art methods by large margins. Notably, to our
knowledge, it is the first to sustain 100K edits and 72B-parameter models,10 x
beyond prior practice, without sacrificing general capabilities. By clarifying
a long-standing misconception and introducing a principled localized tuning
strategy, we advance fine-tuning from an underestimated baseline to a leading
method for model editing, establishing a solid foundation for future research.