Attribution is like when Mom asks who made a mess in the living room. If you did it, you should say so and take the blame. That's attribution!
In marketing, attribution is about figuring out which advertisement or marketing message convinced people to buy something. It's like a detective trying to figure out who solved a crime!
When you buy something, there are usually many different advertisements and marketing messages that you see before you make the purchase. Attribution tries to figure out which one of these messages had the biggest impact on your decision to buy. Was it the TV commercial you saw last night? Or the Facebook ad you saw this morning?
By figuring out which message was most effective, marketers can make better decisions about which advertisements to run in the future. Just like how Mom knows not to leave a box of cookies on the counter if she doesn't want you to eat them, marketers learn which messages work best to get you to buy their products.