For-Value: Efficient Forward-Only Data Valuation for finetuning LLMs and VLMs
Authors: Wenlong Deng, Qi Zeng, Jiaming Zhang, Minghui Chen, Zixin Ding, Christos Thrampoulidis, Boying Gong, Xiaoxiao Li
Published in: Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics, Volume 1: Long Papers (ACL 2026), July 2026, pp. 14581–14600
Overview
For-Value estimates data influence using final-layer representations and prediction errors. A closed-form calculation replaces backpropagation, allowing examples to be evaluated in batches with a single forward pass. The paper evaluates the method on influential-data detection and mislabeled-data identification for language and vision-language models.