What is the analogy for real life cohorts?

Question

Analytics

I try to convey to my colleagues what cohorts are and what advantages they provide.
I prepared several presentations, showed the difference with examples, but I still feel that people do not understand the essence.
I want to explain to them the concept of cohorts on an analogy from real life.
What analogy do you think is best for people to understand what cohorts are and why they should be used instead of slices and averages?

Answer 1

Well, the school, for example, the average score in the 11th grade is 3.4, and if you take cohorts like 11-a, 11-b, etc. picture may be different

Answer 2

https://habrahabr.ru/company/io/blog/262025/