| Summary: | Data mining classification techniques are affected by the presence of imbalances between classes of a response variable. The difficulty in handling the imbalanced data issue has led to an influx of methods, either resolving the imbalance issue at data or algorithmic level. The R programming language is one of the many tools available for data mining. This paper compares some classification algorithms in R for an imbalanced medical data set. The classifiers ADABOOST, KNN, SVM-RBF and logistic regression were applied to the original, random oversampling and undersampling data sets. Results show that ADABOOST, KNN and SVM-RBF exhibits over-fitting when applied to the original dataset. No over-fitting occurs for the random oversampling dataset where by SVM-RBF has the highest accuracy (Training: 91.5%, Testing: 90.6%), sensitivity (Training:91.0%, Testing: 91.0%), specificity (Training: 92.0%,Testing: 90.2%) and precision (Training:91.9%, Testing 90.5%) for training and testing data set. For random undersampling, no over-fitting occurs only for ADABOOST and logistic regression. Logistic regression is the most stable classifier exhibiting consistent training an testing results. © Springer Science+Business Media Singapore 2015.
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