Assitan Koné
Dec 6

What's the Gini index for machine learning?

Why does the Gini index is used for?

The Gini index is used for decision trees. Indeed, how do we know how to separate the root node? Well, there are a couple of methods, and the Gini index is a good one. It allows checking if the leaves containing labels are pure or impure.
That's right, the more diverse the leaves are, the higher the Gini index is. Why? Because if, let's say, you want to recommend a product using a decision tree, you want to make sure that the leaves are the most homogeneous possible so that you can be confident in your proposition.

Formula

When we glance, we can think that feature A gives leaves with less diversity, so a better score, because we have 3 purple circles and two red circles. But you know what, let’s be a bit more rigorous.
So to choose which feature we use as the root tree, we calculate the diversity of the leaves.
This is the formula:

Score

Then we compare the mean of each tree and choose the lowest number. Our winner is feature A!

Author

Assitan Koné
Founder @Codistwa
Empty space, drag to resize

SHARE

Write your awesome label here.

Machine Learning & Deep Learning Algorithms Explained Visually

Write your awesome label here.
Are you tired of wading through dense textbooks and confusing jargon just to grasp the basics of machine learning and deep learning? Say goodbye to the old, ineffective methods and welcome a new era of learning.
Sign up. Be inspired. Code.

Get a FREE Machine Learning Roadmap!

Subscribe to our newsletter to get your gift.

Get tips to teach yourself data science without being overwelmed in your email box. Get secrets to think and act like a Data Scientist on a daily basis. 
Write your awesome label here.
Created with