If you go to a player's homepage, it will show their opponents' average rating for the last 90 days. So, player "A" could have the exact same rating as player "B" , but have faced much tougher opponents in the last 90 days. So , as Duchess64 says, there are statistics involved...
@jb70said I gave up Clan playing because I lost all confidence in the TER being an honest indication of the ability of a clan player. Players shedding points in non-clan games to lower their rating.
I've been losing tournament games on here when the tide suddenly turns and I win.
And so I go look at their profile and scroll down and say yes just as I thought a clan player.
So to all the clan players who have donated points to me over the years- thanks but no thanks.
The website's Terms of Service don't seem to mention sandbagging. I find this curious because they do bar use of computer analysis engines and getting advice from third parties.
A fix to the clan issue would be separate clan rating. The intital rating would be the same as your general rating, but after that, only clan games would effect the clan rating.