The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen’s Kappa and Brier Score in Binary Classification Assessment

Even if measuring the outcome of binary classifications is a pivotal task in machine learning and statistics, no consensus has been reached yet about which statistical rate to employ to this end. In the last century, the computer science and statistics communities have introduced several scores summ...

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Main Authors: Davide Chicco, Matthijs J. Warrens, Giuseppe Jurman
Format: Article
Language:English
Published: IEEE 2021-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/9440903/
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author Davide Chicco
Matthijs J. Warrens
Giuseppe Jurman
author_facet Davide Chicco
Matthijs J. Warrens
Giuseppe Jurman
author_sort Davide Chicco
collection DOAJ
description Even if measuring the outcome of binary classifications is a pivotal task in machine learning and statistics, no consensus has been reached yet about which statistical rate to employ to this end. In the last century, the computer science and statistics communities have introduced several scores summing up the correctness of the predictions with respect to the ground truth values. Among these scores, the Matthews correlation coefficient (MCC) was shown to have several advantages over confusion entropy, accuracy, F<sub>1</sub> score, balanced accuracy, bookmaker informedness, markedness, and diagnostic odds ratio: MCC, in fact, produces a high score only if the majority of the predicted negative data instances and the majority of the positive data instances are correct, and therefore it results being very trustworthy on imbalanced datasets. In this study, we compare MCC with two other popular scores: Cohen&#x2019;s Kappa, a metric that originated in social sciences, and the Brier score, a strictly proper scoring function which emerged in weather forecasting studies. After explaining the mathematical properties and the relationships between MCC and each of these two rates, we report some use cases where these scores generate different values, which lead to discordant outcomes, where MCC provides a more truthful and informative result. We highlight the reasons why it is more advisable to use MCC rather that Cohen&#x2019;s Kappa and the Brier score to evaluate binary classifications.
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spelling doaj.art-91ef0226db1248cf90447c75247d23bc2022-12-21T18:47:18ZengIEEEIEEE Access2169-35362021-01-019783687838110.1109/ACCESS.2021.30840509440903The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification AssessmentDavide Chicco0https://orcid.org/0000-0001-9655-7142Matthijs J. Warrens1https://orcid.org/0000-0002-7302-640XGiuseppe Jurman2https://orcid.org/0000-0002-2705-5728Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, CanadaGroningen Institute for Educational Research, University of Groningen, Groningen, The NetherlandsData Science for Health Unit, Fondazione Bruno Kessler, Trento, ItalyEven if measuring the outcome of binary classifications is a pivotal task in machine learning and statistics, no consensus has been reached yet about which statistical rate to employ to this end. In the last century, the computer science and statistics communities have introduced several scores summing up the correctness of the predictions with respect to the ground truth values. Among these scores, the Matthews correlation coefficient (MCC) was shown to have several advantages over confusion entropy, accuracy, F<sub>1</sub> score, balanced accuracy, bookmaker informedness, markedness, and diagnostic odds ratio: MCC, in fact, produces a high score only if the majority of the predicted negative data instances and the majority of the positive data instances are correct, and therefore it results being very trustworthy on imbalanced datasets. In this study, we compare MCC with two other popular scores: Cohen&#x2019;s Kappa, a metric that originated in social sciences, and the Brier score, a strictly proper scoring function which emerged in weather forecasting studies. After explaining the mathematical properties and the relationships between MCC and each of these two rates, we report some use cases where these scores generate different values, which lead to discordant outcomes, where MCC provides a more truthful and informative result. We highlight the reasons why it is more advisable to use MCC rather that Cohen&#x2019;s Kappa and the Brier score to evaluate binary classifications.https://ieeexplore.ieee.org/document/9440903/Matthews correlation coefficientCohen’s Kappabinary classificationconfusion matrixsupervised machine learningBrier score
spellingShingle Davide Chicco
Matthijs J. Warrens
Giuseppe Jurman
The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
IEEE Access
Matthews correlation coefficient
Cohen’s Kappa
binary classification
confusion matrix
supervised machine learning
Brier score
title The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
title_full The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
title_fullStr The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
title_full_unstemmed The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
title_short The Matthews Correlation Coefficient (MCC) is More Informative Than Cohen&#x2019;s Kappa and Brier Score in Binary Classification Assessment
title_sort matthews correlation coefficient mcc is more informative than cohen x2019 s kappa and brier score in binary classification assessment
topic Matthews correlation coefficient
Cohen’s Kappa
binary classification
confusion matrix
supervised machine learning
Brier score
url https://ieeexplore.ieee.org/document/9440903/
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