DEV Community

Bharath Prasad
Bharath Prasad

Posted on

A Beginner’s Guide to Semi-Supervised Learning in Machine Learning

If you’re new to machine learning, you may have come across terms like supervised, unsupervised, and semi-supervised learning. The first two are easy to understand. One has full guidance, the other has none. But what does semi-supervised mean?

Let’s break it down in a simple way.

Imagine you’re asked to sort fruits. Someone gives you the names of just five fruits, but you have a basket of 500. You use the five examples to guess the rest. This is exactly how semi-supervised learning works.

What Is Semi-Supervised Learning?
It is a technique where the model learns from a small amount of labelled data and a large amount of unlabelled data. This method saves both time and cost because labelling data is a long and boring task.

Why Use It?
Labelled data is limited – Creating it needs time and money.

Unlabelled data is easy to find – From websites, apps, social media, etc.

It gives better results than using unlabelled data alone.

Where Is It Used?
Spam filters (Gmail)

Voice recognition (Alexa, Google)

Medical scans (X-rays)

E-commerce suggestions (Amazon)

Face recognition (social media)

Simple Algorithms You Can Explore
Self-training

Co-training

Graph-based learning

Semi-supervised SVM

Generative models

Each has its own way of using both labelled and unlabelled data.

When Should You Try This?
Use semi-supervised learning when:

You have very little labelled data

You have large unlabelled datasets

You want decent performance without too much manual effort

Final Words

Semi-supervised learning is becoming popular in real-world machine learning projects, especially in India where start-ups and small businesses work with limited data. If you're learning ML or planning your first project, this is a great place to start.

Let us know if you're exploring this method—we’d love to hear your experience.

Top comments (0)