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Main Authors: Campos, Margarida M., Calém, João, Sklaviadis, Sophia, Figueiredo, Mário A. T., Martins, André F. T.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.14773
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author Campos, Margarida M.
Calém, João
Sklaviadis, Sophia
Figueiredo, Mário A. T.
Martins, André F. T.
author_facet Campos, Margarida M.
Calém, João
Sklaviadis, Sophia
Figueiredo, Mário A. T.
Martins, André F. T.
contents Conformal prediction is a distribution-free framework for uncertainty quantification that replaces point predictions with sets, offering marginal coverage guarantees (i.e., ensuring that the prediction sets contain the true label with a specified probability, in expectation). In this paper, we uncover a novel connection between conformal prediction and sparse softmax-like transformations, such as sparsemax and $γ$-entmax (with $γ> 1$), which may assign nonzero probability only to a subset of labels. We introduce new non-conformity scores for classification that make the calibration process correspond to the widely used temperature scaling method. At test time, applying these sparse transformations with the calibrated temperature leads to a support set (i.e., the set of labels with nonzero probability) that automatically inherits the coverage guarantees of conformal prediction. Through experiments on computer vision and text classification benchmarks, we demonstrate that the proposed method achieves competitive results in terms of coverage, efficiency, and adaptiveness compared to standard non-conformity scores based on softmax.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14773
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sparse Activations as Conformal Predictors
Campos, Margarida M.
Calém, João
Sklaviadis, Sophia
Figueiredo, Mário A. T.
Martins, André F. T.
Machine Learning
Conformal prediction is a distribution-free framework for uncertainty quantification that replaces point predictions with sets, offering marginal coverage guarantees (i.e., ensuring that the prediction sets contain the true label with a specified probability, in expectation). In this paper, we uncover a novel connection between conformal prediction and sparse softmax-like transformations, such as sparsemax and $γ$-entmax (with $γ> 1$), which may assign nonzero probability only to a subset of labels. We introduce new non-conformity scores for classification that make the calibration process correspond to the widely used temperature scaling method. At test time, applying these sparse transformations with the calibrated temperature leads to a support set (i.e., the set of labels with nonzero probability) that automatically inherits the coverage guarantees of conformal prediction. Through experiments on computer vision and text classification benchmarks, we demonstrate that the proposed method achieves competitive results in terms of coverage, efficiency, and adaptiveness compared to standard non-conformity scores based on softmax.
title Sparse Activations as Conformal Predictors
topic Machine Learning
url https://arxiv.org/abs/2502.14773