AIExplainer
Machine Learning Intermediate 1 min read

What is one-vs.-all?

A machine learning strategy used for multi-class classification problems

One-vs.-all is a technique where a single classifier is trained to distinguish one class from all the other classes combined, and this process is repeated for each class

Imagine you're trying to identify different types of fruit. In one-vs.-all, you would first train a model to distinguish apples from all other fruits, then train another model to distinguish bananas from all other fruits, and so on

A spam filter using one-vs.-all could train one model to identify spam emails versus non-spam emails, and another model to identify promotional emails versus non-promotional emails

This strategy is often used in machine learning algorithms such as support vector machines and logistic regression to solve multi-class classification problems

One common misconception is that one-vs.-all is the only approach to multi-class classification, when in fact there are other strategies such as one-vs.-one and all-vs.-all

The one-vs.-all strategy has been used in machine learning for decades, and is a well-established technique in the field

one-against-all one-vs.-rest

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