Conformal Prediction for Compositional Data

Fuente: arXiv
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Main Authors: Amaral, Lucas P., Cabezas, Luben M. C., Ramos, Thiago R., Pereira, Gustavo H. G. A.
Format: Preprint
Published: 2025
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author Amaral, Lucas P.
Cabezas, Luben M. C.
Ramos, Thiago R.
Pereira, Gustavo H. G. A.
author_facet Amaral, Lucas P.
Cabezas, Luben M. C.
Ramos, Thiago R.
Pereira, Gustavo H. G. A.
contents Dirichlet regression models are suitable for compositional data, in which the response variable represents proportions that sum to one. However, there are still no well-established methods for constructing valid prediction sets in this context, especially considering the geometry of the compositional space. In this work, we investigate conformal prediction-based strategies for constructing valid predictive regions in Dirichlet regression models. We evaluate three distinct approaches: a method based on quantile residuals, an approximate construction of highest density regions (HDR), and an adaptation of the approximate HDR using grid-based discretization over the simplex. The performance of the methods was analyzed through simulation studies under different scenarios, varying the model complexity, response dimensionality, and covariate structure. The results indicated that the HDR approximation approach exhibits good robustness in terms of coverage, while the grid discretization proved effective in reducing overcoverage and the area of the prediction region compared to the original method. The quantile method provided larger prediction regions compared to the grid method, while maintaining adequate coverage. The methodologies were also applied to two real datasets: one concerning sleep stages and another on biomass allocation in plants. In both cases, the proposed methods demonstrated practical feasibility and produced coherent interpretations within the compositional space. Finally, we discuss possible extensions of this work
format Preprint
id arxiv_https___arxiv_org_abs_2511_18141
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Conformal Prediction for Compositional Data
Amaral, Lucas P.
Cabezas, Luben M. C.
Ramos, Thiago R.
Pereira, Gustavo H. G. A.
Machine Learning
Dirichlet regression models are suitable for compositional data, in which the response variable represents proportions that sum to one. However, there are still no well-established methods for constructing valid prediction sets in this context, especially considering the geometry of the compositional space. In this work, we investigate conformal prediction-based strategies for constructing valid predictive regions in Dirichlet regression models. We evaluate three distinct approaches: a method based on quantile residuals, an approximate construction of highest density regions (HDR), and an adaptation of the approximate HDR using grid-based discretization over the simplex. The performance of the methods was analyzed through simulation studies under different scenarios, varying the model complexity, response dimensionality, and covariate structure. The results indicated that the HDR approximation approach exhibits good robustness in terms of coverage, while the grid discretization proved effective in reducing overcoverage and the area of the prediction region compared to the original method. The quantile method provided larger prediction regions compared to the grid method, while maintaining adequate coverage. The methodologies were also applied to two real datasets: one concerning sleep stages and another on biomass allocation in plants. In both cases, the proposed methods demonstrated practical feasibility and produced coherent interpretations within the compositional space. Finally, we discuss possible extensions of this work
title Conformal Prediction for Compositional Data
topic Machine Learning
url https://arxiv.org/abs/2511.18141