ELI5: What is the difference between synthetic data and real data

Real data is information collected from the actual world, while synthetic data is information made up to look like real data.

Imagine you want to learn how to bake cookies.

• Real data would be like using your grandma's secret cookie recipe, with ingredients and instructions based on her years of real-world baking experience. You're actually making cookies and measuring real things.

• Synthetic data would be like using a computer program to generate a fake cookie recipe. The program might look at lots of real cookie recipes and then create a new one that seems believable, but it's not based on someone actually baking cookies.

• Real data is like taking pictures of your friends. You see their actual faces, hair, and clothes.

• Synthetic data is like using a cartoon drawing of people that kind of resemble your friends, but they are not the real thing.

• Sometimes, getting real data is hard or expensive. For example, imagine you want to test a new self-driving car. It's dangerous to let it drive around on real roads without lots of testing! So, engineers might use synthetic data to simulate roads, traffic, and pedestrians in a virtual world. The car can "drive" in the simulation without crashing into anything in real life.

• Sometimes, we want to protect people's privacy. If we collect real data about people's health, we have to be very careful not to reveal their names or addresses. Synthetic data can be used to create fake health records that still look like real ones, but don't contain any personal information. This allows researchers to study health trends without violating anyone's privacy.