Evaluating the performance of machine learning models is crucial to ensure they are working accurately. However, when dealing with imbalanced datasets, traditional evaluation metrics may not give an accurate representation of a model’s performance. In this article, we explore different approaches to address this challenge and provide a benchmark dataset for comparing various techniques.
The authors highlight the problem of evaluating machine learning models on imbalanced datasets, where one class has a significantly larger number of instances than the other classes. This can lead to biased models that perform poorly on minority classes. To overcome this issue, several techniques are proposed:
- Synthetic Minority Over-sampling Technique (SMOTE): This involves creating synthetic examples of the minority class by interpolating between existing instances. By increasing the number of minority class instances, the model is less biased towards the majority class.
- Borderline-SMOTE: This technique improves upon SMOTE by selecting the most informative samples to oversample, rather than randomly selecting them.
- Ensemble-based approaches: Combining multiple models can help reduce bias by averaging their predictions.
- Cost-sensitive learning: Assigning different costs to misclassification errors based on their severity can help the model focus more on the minority class.
The authors provide a benchmark dataset, called VQM (Visual Questions for Machine Learning), which contains 1000 questions with images and associated labels. The dataset is imbalanced, with 85% of the instances belonging to one class. Users can evaluate their models on this dataset and compare their performance to existing techniques.
In summary, evaluating machine learning models on imbalanced datasets can be challenging, but several techniques can help improve their performance. By using these approaches, users can create a more accurate model that performs well on both majority and minority classes. The VQM dataset provides a practical benchmark for testing and comparing different methods.