Reconciling Functional Data Regression with Excess Bases

Fuente: arXiv
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Main Authors: Wakayama, Tomoya, Matsui, Hidetoshi
Format: Preprint
Published: 2023
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author Wakayama, Tomoya
Matsui, Hidetoshi
author_facet Wakayama, Tomoya
Matsui, Hidetoshi
contents As the development of measuring instruments and computers has accelerated the collection of massive amounts of data, functional data analysis (FDA) has experienced a surge of attention. The FDA methodology treats longitudinal data as a set of functions on which inference, including regression, is performed. Functionalizing data typically involves fitting the data with basis functions. In general, the number of basis functions smaller than the sample size is selected. This paper casts doubt on this convention. Recent statistical theory has revealed the so-called double-descent phenomenon in which excess parameters overcome overfitting and lead to precise interpolation. Applying this idea to choosing the number of bases to be used for functional data, we show that choosing an excess number of bases can lead to more accurate predictions. Specifically, we explored this phenomenon in a functional regression context and examined its validity through numerical experiments. In addition, we introduce two real-world datasets to demonstrate that the double-descent phenomenon goes beyond theoretical and numerical experiments, confirming its importance in practical applications.
format Preprint
id arxiv_https___arxiv_org_abs_2308_01724
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Reconciling Functional Data Regression with Excess Bases
Wakayama, Tomoya
Matsui, Hidetoshi
Methodology
As the development of measuring instruments and computers has accelerated the collection of massive amounts of data, functional data analysis (FDA) has experienced a surge of attention. The FDA methodology treats longitudinal data as a set of functions on which inference, including regression, is performed. Functionalizing data typically involves fitting the data with basis functions. In general, the number of basis functions smaller than the sample size is selected. This paper casts doubt on this convention. Recent statistical theory has revealed the so-called double-descent phenomenon in which excess parameters overcome overfitting and lead to precise interpolation. Applying this idea to choosing the number of bases to be used for functional data, we show that choosing an excess number of bases can lead to more accurate predictions. Specifically, we explored this phenomenon in a functional regression context and examined its validity through numerical experiments. In addition, we introduce two real-world datasets to demonstrate that the double-descent phenomenon goes beyond theoretical and numerical experiments, confirming its importance in practical applications.
title Reconciling Functional Data Regression with Excess Bases
topic Methodology
url https://arxiv.org/abs/2308.01724