Calculating the rating for clans!

to AmberSoler: we need to think about this... And why exactly three? Why not four or five? Or maybe two?
The advantages of this system are obvious (and very good), but there are also disadvantages... By the way, you say:

Rating - only for those clans that have a qualifying minimum number of players required for the calculation

I don't agree with this; it should be: "Rating - only for those clans that have a qualifying number of players required for the calculation," i.e., a specific number of players for all clans.