Rethinking Residual Distribution in Locate-then-Edit Model Editing

Fuente: arXiv
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Hauptverfasser: Li, Xiaopeng, Wang, Shanwen, Li, Shasha, Song, Shezheng, Ji, Bin, Ma, Jun, Yu, Jie
Format: Preprint
Veröffentlicht: 2025
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author Li, Xiaopeng
Wang, Shanwen
Li, Shasha
Song, Shezheng
Ji, Bin
Ma, Jun
Yu, Jie
author_facet Li, Xiaopeng
Wang, Shanwen
Li, Shasha
Song, Shezheng
Ji, Bin
Ma, Jun
Yu, Jie
contents Model editing enables targeted updates to the knowledge of large language models (LLMs) with minimal retraining. Among existing approaches, locate-then-edit methods constitute a prominent paradigm: they first identify critical layers, then compute residuals at the final critical layer based on the target edit, and finally apply least-squares-based multi-layer updates via $\textbf{residual distribution}$. While empirically effective, we identify a counterintuitive failure mode: residual distribution, a core mechanism in these methods, introduces weight shift errors that undermine editing precision. Through theoretical and empirical analysis, we show that such errors increase with the distribution distance, batch size, and edit sequence length, ultimately leading to inaccurate or suboptimal edits. To address this, we propose the $\textbf{B}$oundary $\textbf{L}$ayer $\textbf{U}$pdat$\textbf{E (BLUE)}$ strategy to enhance locate-then-edit methods. Sequential batch editing experiments on three LLMs and two datasets demonstrate that BLUE not only delivers an average performance improvement of 35.59\%, significantly advancing the state of the art in model editing, but also enhances the preservation of LLMs' general capabilities. Our code is available at https://github.com/xpq-tech/BLUE.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03748
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rethinking Residual Distribution in Locate-then-Edit Model Editing
Li, Xiaopeng
Wang, Shanwen
Li, Shasha
Song, Shezheng
Ji, Bin
Ma, Jun
Yu, Jie
Computation and Language
Model editing enables targeted updates to the knowledge of large language models (LLMs) with minimal retraining. Among existing approaches, locate-then-edit methods constitute a prominent paradigm: they first identify critical layers, then compute residuals at the final critical layer based on the target edit, and finally apply least-squares-based multi-layer updates via $\textbf{residual distribution}$. While empirically effective, we identify a counterintuitive failure mode: residual distribution, a core mechanism in these methods, introduces weight shift errors that undermine editing precision. Through theoretical and empirical analysis, we show that such errors increase with the distribution distance, batch size, and edit sequence length, ultimately leading to inaccurate or suboptimal edits. To address this, we propose the $\textbf{B}$oundary $\textbf{L}$ayer $\textbf{U}$pdat$\textbf{E (BLUE)}$ strategy to enhance locate-then-edit methods. Sequential batch editing experiments on three LLMs and two datasets demonstrate that BLUE not only delivers an average performance improvement of 35.59\%, significantly advancing the state of the art in model editing, but also enhances the preservation of LLMs' general capabilities. Our code is available at https://github.com/xpq-tech/BLUE.
title Rethinking Residual Distribution in Locate-then-Edit Model Editing
topic Computation and Language
url https://arxiv.org/abs/2502.03748