Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence

Class imbalance is a persistent challenge in machine learning, particularly in high-stakes applications such as medical diagnostics, bioinformatics, and fraud detection, where the minority class often represents critical cases. While prior research has examined the effect of imbalance on classifier...

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Autores principales: Arshad, Iqra, Umair, Muhammad, Jan, Faheem, Iftikhar, Hasnain, Canas Rodrigues, Paulo, Ivan Gonzales Medina, Ronny, López Gonzales, Javier Linkolk
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Lenguaje:inglés
Publicado: 2025
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author Arshad, Iqra
Umair, Muhammad
Jan, Faheem
Iftikhar, Hasnain
Canas Rodrigues, Paulo
Ivan Gonzales Medina, Ronny
López Gonzales, Javier Linkolk
author_browse Arshad, Iqra
Canas Rodrigues, Paulo
Iftikhar, Hasnain
Ivan Gonzales Medina, Ronny
Jan, Faheem
López Gonzales, Javier Linkolk
Umair, Muhammad
author_facet Arshad, Iqra
Umair, Muhammad
Jan, Faheem
Iftikhar, Hasnain
Canas Rodrigues, Paulo
Ivan Gonzales Medina, Ronny
López Gonzales, Javier Linkolk
author_sort Arshad, Iqra
collection Producción científica
description Class imbalance is a persistent challenge in machine learning, particularly in high-stakes applications such as medical diagnostics, bioinformatics, and fraud detection, where the minority class often represents critical cases. While prior research has examined the effect of imbalance on classifier performance, little attention has been paid to establishing practical guidelines for the minimum proportion of minority samples required to achieve reliable sensitivity. In this study, we conduct extensive simulations using synthetic datasets and evaluate five widely used classification algorithms: Logistic Regression (Logit), Support Vector Machines (SVM), Random Forest, XGBoost, and Neural Networks (NNs). Our analysis reveals that logistic regression is more effective in identifying minority-class instances under an imbalanced class distribution in terms of F1 score and sensitivity, whereas Neural Network slightly performs better for a balanced-class distribution than logistic regression. Importantly, we identify a practical threshold for minority class representation: classifier sensitivity declines sharply when positive samples fall below approximately 25–30%. This finding is validated on eight real-world datasets, including large-scale applications, where Neural Networks and XGBoost demonstrate superior sensitivity. By establishing an actionable threshold, this study contributes practical guidance for dataset design and model selection in imbalanced classification problems.
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spelling oai:cris.upeu.edu.pe:20.500.15037/4072026-11-02T22:00:04ZPerformance of Classification Algorithms Under Class Imbalance: Simulation and Real-World EvidenceArshad, IqraUmair, MuhammadJan, FaheemIftikhar, HasnainCanas Rodrigues, PauloIvan Gonzales Medina, RonnyLópez Gonzales, Javier LinkolkClass imbalance is a persistent challenge in machine learning, particularly in high-stakes applications such as medical diagnostics, bioinformatics, and fraud detection, where the minority class often represents critical cases. While prior research has examined the effect of imbalance on classifier performance, little attention has been paid to establishing practical guidelines for the minimum proportion of minority samples required to achieve reliable sensitivity. In this study, we conduct extensive simulations using synthetic datasets and evaluate five widely used classification algorithms: Logistic Regression (Logit), Support Vector Machines (SVM), Random Forest, XGBoost, and Neural Networks (NNs). Our analysis reveals that logistic regression is more effective in identifying minority-class instances under an imbalanced class distribution in terms of F1 score and sensitivity, whereas Neural Network slightly performs better for a balanced-class distribution than logistic regression. Importantly, we identify a practical threshold for minority class representation: classifier sensitivity declines sharply when positive samples fall below approximately 25–30%. This finding is validated on eight real-world datasets, including large-scale applications, where Neural Networks and XGBoost demonstrate superior sensitivity. By establishing an actionable threshold, this study contributes practical guidance for dataset design and model selection in imbalanced classification problems.Articlehttps://doi.org/10.1109/access.2025.362026410.1109/access.2025.3620264https://hdl.handle.net/20.500.15037/407W4415048073enIEEE Access2169-35362025-01-012026-06-13T08:12:53Z2026-06-13T08:12:53Z
spellingShingle Arshad, Iqra
Umair, Muhammad
Jan, Faheem
Iftikhar, Hasnain
Canas Rodrigues, Paulo
Ivan Gonzales Medina, Ronny
López Gonzales, Javier Linkolk
Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title_full Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title_fullStr Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title_full_unstemmed Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title_short Performance of Classification Algorithms Under Class Imbalance: Simulation and Real-World Evidence
title_sort performance of classification algorithms under class imbalance simulation and real world evidence
url https://doi.org/10.1109/access.2025.3620264
https://hdl.handle.net/20.500.15037/407
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