CHAPTER 04 · HOW AI LEARNS

Decision trees and classic ML models

Plenty of tasks do not need huge neural networks.

What is it?

Classic machine learning models, such as decision trees, random forests and linear models, solve many everyday tasks without large neural networks. They are fast, cheap and often easier to explain.

An everyday example

A bank assesses loan risk with a tree of questions: what is the income, does the applicant have other loans, how long have they been employed?

Why does it matter?

For tabular data, classic models are often as good as or better than large models, and their decisions are easier to check.

A common misconception

That the biggest and newest model is always the best choice. The best model is the one that reliably solves the actual task.

In more detail

What is a decision tree?

A model that picks a prediction or category through a series of checkable questions.

What is a random forest?

A method that combines many trees to give a more stable prediction.

What are linear models?

Models that link data through an assumed form of mathematical relationship.

When are they useful?

When we need faster deployment, less data, lower costs or a more explainable result.

Remember: The best model for the job is not necessarily the biggest.

Reliable sources

Last reviewed 1 November 2026. An explainer, not professional, legal or medical advice. For rules and figures that change, check the official version.