Where is this stated?
This is how it should be, yes?
This is basically how it is.
There is a large variation in skill at a given SR, but that is because SR/MMR is inaccurate. It is not caused by any hidden MMR mechanism. Among other things, for active players, MMR and SR are in sync (Overwatch Forums ). So inaccuracies in SR are matched by inaccuracies in MMR.
To summarize the system:
MMR is a (hidden) number that goes up when you win, and down when you lose. How much it goes up and down is a complicated formula, based on many factors, but the essential truth of wins are good and losses are bad is certain (4).
That MMR is then used to match people with and against people of similar MMR, in an attempt to create a 50% match (32). Here is the key part:
If a player’s MMR is wrong and too low, then the odds to win will be greater than 50%, and the player will win more games than he loses, which will cause his MMR to rise over many games played. He will then be placed with stronger and stronger opponents (and stronger and stronger allies) until his MMR is correct, and his win percentage approaches 50% (with some random oscillation around 50%) (7).
Once a player finds himself trapped in a rating range, the only way to break out is to improve as a player and play enough games to overcome any random factors (47).
What is SR then? SR is a visible and friendlier approximation of MMR (23). It has no more meaning with respect to matchmaking than tier icons. However, except for top players who have decayed, MMR and SR are closely linked, so inspecting SR typically gives a reasonable estimate of a player’s MMR (23).
(4) Overwatch Forums “In Overwatch, whether your MMR goes up or down is contingent on winning or losing. But there are a number of factors that determine how much that rating goes up or down.”Overwatch Forums Overwatch Forums Overwatch Forums Twitch