Task Shift: From Classification to Regression in Overparameterized Linear Models

Fuente: arXiv
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Main Authors: LaBonte, Tyler, Lai, Kuo-Wei, Muthukumar, Vidya
Format: Preprint
Published: 2025
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author LaBonte, Tyler
Lai, Kuo-Wei
Muthukumar, Vidya
author_facet LaBonte, Tyler
Lai, Kuo-Wei
Muthukumar, Vidya
contents Modern machine learning methods have recently demonstrated remarkable capability to generalize under task shift, where latent knowledge is transferred to a different, often more difficult, task under a similar data distribution. We investigate this phenomenon in an overparameterized linear regression setting where the task shifts from classification during training to regression during evaluation. In the zero-shot case, wherein no regression data is available, we prove that task shift is impossible in both sparse signal and random signal models for any Gaussian covariate distribution. In the few-shot case, wherein limited regression data is available, we propose a simple postprocessing algorithm which asymptotically recovers the ground-truth predictor. Our analysis leverages a fine-grained characterization of individual parameters arising from minimum-norm interpolation which may be of independent interest. Our results show that while minimum-norm interpolators for classification cannot transfer to regression a priori, they experience surprisingly structured attenuation which enables successful task shift with limited additional data.
format Preprint
id arxiv_https___arxiv_org_abs_2502_13285
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Task Shift: From Classification to Regression in Overparameterized Linear Models
LaBonte, Tyler
Lai, Kuo-Wei
Muthukumar, Vidya
Machine Learning
Modern machine learning methods have recently demonstrated remarkable capability to generalize under task shift, where latent knowledge is transferred to a different, often more difficult, task under a similar data distribution. We investigate this phenomenon in an overparameterized linear regression setting where the task shifts from classification during training to regression during evaluation. In the zero-shot case, wherein no regression data is available, we prove that task shift is impossible in both sparse signal and random signal models for any Gaussian covariate distribution. In the few-shot case, wherein limited regression data is available, we propose a simple postprocessing algorithm which asymptotically recovers the ground-truth predictor. Our analysis leverages a fine-grained characterization of individual parameters arising from minimum-norm interpolation which may be of independent interest. Our results show that while minimum-norm interpolators for classification cannot transfer to regression a priori, they experience surprisingly structured attenuation which enables successful task shift with limited additional data.
title Task Shift: From Classification to Regression in Overparameterized Linear Models
topic Machine Learning
url https://arxiv.org/abs/2502.13285