research area Data Science and Annotation, research area Privacy
content type paperpublished July 2026

When Unlearning Is Free: Leveraging Low Influence Points to Reduce Computational Costs

AuthorsAnat Kleiman†**, Robert Fisher, Ben Deaner‡, Udi Wieder, Vitaly Feldman

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As concerns around data privacy in machine learning grow, the ability to unlearn—or remove—specific data points from trained models becomes increasingly important. While state-of-the-art unlearning methods have emerged in response, they typically treat all points in the forget set equally. In this work, we challenge this approach by asking: do points that have a negligible impact on the model’s learning need to be removed? Through a comparative analysis of influence functions across language and vision tasks, we identify subsets of training data with negligible impact on model outputs. Leveraging this insight, we propose an efficient unlearning framework that reduces the size of datasets before unlearning—leading to significant computational savings (up to ~50%) on real-world empirical examples.

  • † Harvard University
  • ‡ University College London (UCL)
  • ** Work done while at Apple

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