Structure Data

In our newsletter last week, there was a blurb on leaving teachers. It said their name, role, and how long they had worked at the school.

I am interested in odd things, so I wondered what the average number of years teachers stayed at this school.

I think aside from the amount of leaving staff for the size of the school, this is pretty usual. 

Then I started to add staff who have left in the past. Then I was wondering about current staff and now this is turning into an interesting personal project about how to structure data. 

I wanted to see what the average tenure of the teaching staff was, but then I could start asking questions about the max and minimum stay of teachers. 

I don't have the data for the reasons why teachers came or left, but that would be good to collect. 

Currently, I have teachers who have left and current teachers on different sheets, but I think they should all go on a single sheet with a dropdown for those who have left and stayed.