Community-based participatory research, or CBPR for short, is when grown-ups in different jobs work together with people who live in a community to study a problem and find ways to solve it.
Imagine you and your friends notice that there is always a lot of litter in the park where you like to play. You might tell your grown-ups about it, but they might not know what to do about it. That's where CBPR comes in.
First, some grown-ups who are scientists or researchers would ask the people who live in the community (including you and your friends!) about the problem. They might ask you questions like, "What kinds of litter do you see in the park?" and "Why do you think people throw trash on the ground instead of in the trash can?"
Then, the grown-ups and people in the community might work together to come up with some ways to solve the problem. For example, you and your friends might suggest putting up signs to remind people to throw their trash away, or having a contest to see who can pick up the most litter in a certain amount of time. The grown-ups might also have ideas, like having a city-wide cleanup day or building more trash cans in the park.
Finally, the scientists or researchers would study whether the ideas worked by looking at how much litter there is in the park now compared to before the changes were made. If the amount of litter goes down, that means the ideas worked and the community is now a cleaner and more enjoyable place to be!