Even when all players agree to a Draw, there is still a rating change for TMM? I've experienced the same thing, and was surprised.
How can you determine a winner/loser if it was a Draw?
But then I checked the games a day later, and they correctly say 'DRAW' and no rating change.
So it all worked out in the end, but that is a bit a confusing!
Fichom - Have you rechecked the game results a day or two later? They may correctly appear as a Draw.
Of course there “could” be but who is going to have time to build that. Detecting who is causing connection issues is also quite difficult and sometimes impossible since how can you decide which end of the pipe is responsible for the connection issue in a peer-to-peer system? That’s assuming you can even see which connections are having issues, which the lobby server can’t. I think nowadays the telemetry server often has that data and you could conceivably send it to the lobby server but there’s yet another nontrivial piece of code someone’s gotta write. All’s to say, yea it’s possible if you got enough devs with enough spare time.
@pviddy said in [Rating] Inconsistency when drawing:
Even when all players agree to a Draw, there is still a rating change for TMM? I've experienced the same thing, and was surprised.
How can you determine a winner/loser if it was a Draw?
Wrong assumptions on your end. A draw can cause rating changes and win of one player might - in theory - not cause a rating change. This depends on what the expected result is.
The rating we should is just a simplified number of the underlying metrics mean (your assumed skill) and the deviation (the probability or confidence your mean is correct).
We calculate the shown rating as rating = mean - 3*deviation.
So if the mean doesn't change because the game predicted this result (and a draw could also be predicted!), the deviation might still be reduced because we are more sure, that the mean matches the true players skill.
And I would still love somebody to build a trueskill calculator to explain this to people in a way they can play around with the values and see themselves.
"Nerds have a really complicated relationship with change: Change is awesome when WE'RE the ones doing it. As soon as change is coming from outside of us it becomes untrustworthy and it threatens what we think of is the familiar."
– Benno Rice
How about not rating matchmaker games if they result in a draw before the same grace period as in custom games?
Pretty much. Your idea in the issue is to not rank games ended by a draw, and I want to add on top of that the grace period condition.
As for the rating manipulation possibilities mentioned there:
TMM games, like all global games should be unrated within that first 8 minutes.
Regardless of who is "expected" to win.
Surely that is easy to change. Apply this rule after 8 minutes.
It's plain stupid that rating changes occur during any kind of draw. It defies the definition of the word draw.
@pviddy That's because of the most recent client update that now doesn't show rating changes in matchmaker games at all. The change still happens, you just don't get informed on it 
@ftxcommando I forgot to add, which is quite important: that is a valid reason. But, at least the Draw mechanic should have a timeout so it's unrated for a sufficiently short games.
