Book Image

Machine Learning for Imbalanced Data

By : Kumar Abhishek, Dr. Mounir Abdelaziz
Book Image

Machine Learning for Imbalanced Data

By: Kumar Abhishek, Dr. Mounir Abdelaziz

Overview of this book

As machine learning practitioners, we often encounter imbalanced datasets in which one class has considerably fewer instances than the other. Many machine learning algorithms assume an equilibrium between majority and minority classes, leading to suboptimal performance on imbalanced data. This comprehensive guide helps you address this class imbalance to significantly improve model performance. Machine Learning for Imbalanced Data begins by introducing you to the challenges posed by imbalanced datasets and the importance of addressing these issues. It then guides you through techniques that enhance the performance of classical machine learning models when using imbalanced data, including various sampling and cost-sensitive learning methods. As you progress, you’ll delve into similar and more advanced techniques for deep learning models, employing PyTorch as the primary framework. Throughout the book, hands-on examples will provide working and reproducible code that’ll demonstrate the practical implementation of each technique. By the end of this book, you’ll be adept at identifying and addressing class imbalances and confidently applying various techniques, including sampling, cost-sensitive techniques, and threshold adjustment, while using traditional machine learning or deep learning models.
Table of Contents (15 chapters)

Model Calibration

So far, we have explored various ways to handle the data imbalance. In this chapter, we will see the need to do some post-processing of the prediction scores that we get from the trained models. This can be helpful either during the real-time prediction from the model or during the offline training time evaluation of the model. We will also understand some ways of measuring how calibrated the model is and how imbalanced datasets make the model calibration inevitable.

The following topics will be covered in the chapter:

  • Introduction to model calibration
  • The influence of data balancing techniques on model calibration
  • Plotting calibration curves for a model trained on a real-world dataset
  • Model calibration techniques
  • The impact of calibration on a model’s performance

By the end of this chapter, you will have a clear understanding of what model calibration means, how to measure it, and when and how to apply it.