Calculating the rating for clans!

First of all, don't go off-topic in other threads! There are dedicated threads for that!

Oh, come on, it wasn't that off-topic :) It's actually quite relevant. I saw an example of people switching from one Clan to another, or even leaving Clans altogether, so this post naturally fit into your thread.

Secondly, to the point:
In my opinion, it's very simple... the rating is calculated based on tournament results, so let's say: player X was in Clan A and played n tournaments, so the rating for these n tournaments is attributed to Clan A, then the player switched to Clan B, and this Clan will only be credited with the rating for new tournaments. i.e., the old rating will remain in Clan A. I think this is the fairest system. Or do you disagree?

I almost agree :) Because, hypothetically, if over time some people leave Clans, and others switch from one Clan to another, what will this Clan rating reflect when people leave their results in one Clan and then earn a rating for another? In my opinion, there's no way to avoid having Clan ratings that age over time :)