Book Image

Hands-On Ensemble Learning with R

By : Prabhanjan Narayanachar Tattar
Book Image

Hands-On Ensemble Learning with R

By: Prabhanjan Narayanachar Tattar

Overview of this book

Ensemble techniques are used for combining two or more similar or dissimilar machine learning algorithms to create a stronger model. Such a model delivers superior prediction power and can give your datasets a boost in accuracy. Hands-On Ensemble Learning with R begins with the important statistical resampling methods. You will then walk through the central trilogy of ensemble techniques – bagging, random forest, and boosting – then you'll learn how they can be used to provide greater accuracy on large datasets using popular R packages. You will learn how to combine model predictions using different machine learning algorithms to build ensemble models. In addition to this, you will explore how to improve the performance of your ensemble models. By the end of this book, you will have learned how machine learning algorithms can be combined to reduce common problems and build simple efficient ensemble models with the help of real-world examples.
Table of Contents (17 chapters)
Hands-On Ensemble Learning with R
Contributors
Preface
12
What's Next?
Index

Chapter 8. Ensemble Diagnostics

In earlier chapters, ensemble methods were found to be effective. In the previous chapter, we looked at scenarios in which ensemble methods increase the overall accuracy of a prediction. It has previously been assumed that different base learners are independent of each other. However, unless we have a very large sample and the base models are learners that use a distinct set of observations, such an assumption is very impractical. Even if we had a large enough sample to believe that the partitions are nonoverlapping, each base model is built on a different partition, and each partition carries with it the same information as any other partition. However, it is difficult to test validations such as this, so we need to employ various techniques in order to validate the independence of the base models on the same dataset. To do this, we will look at various different methods. A brief discussion of the need for ensemble diagnostics will kick off this chapter...