Can you give me an example of the use of cluster randomized design?

I am happy to share.

Thank you.

An example:
An evaluation of an individualized tutoring program at a single school might regard classrooms as clusters and the design decision would involve deciding between randomly assigning all students eligible for tutoring within a given classroom to an experimental or control condition, instead of randomly assigning some students within a given classroom to the experimental group and some to the control group