Im not an expert in MMR, neither a super PVPer, but after reading so much of the forum feedback/venting i can say most people are clueless about it, so i made this post to explain the basics of MMR:
MMR: Match Making Ratio its a skill rating and skill rating system that comes from Glicko 2, glicko 2 of course comes from glicko 1 that in itself is an improvement of ELO.
How you move on the MMR system:
Players are suposed to start at a determinated ratio (1200) and go up or down based on three important points:
- You won or lose.
-Against what MMR (team MMR) you did it, compared to yours.
- How certain the system its of your MMR.
The second point directly destroys the common idea of same win/lose ratio= same MMR, that doesnt normally happen, the system take in account against who you fight.
At the same time this explain why theres difference between skill rating winning and lose between players and why sometimes lose have a bigger value than wins (you had more chances to win).
It also makes so that when the system has litle people or a player group up with a lower MMR guy, he will not farm skill rating, because a meager win of skill rating points (in fact some skill rating systems make you lost a small quantity of points when you win against someone less skilled).
Third one has to do with the deviations: MMR works as an alghoritm, it becomes more precise by each match, the more accurate calculation it has of your true skill rating, the less it will deviate for wins and loses, it will still happens, but less. This is because you will lost and win, as a result your mmr fluctuate up and down between your real place and if this deviations arent restrained partially the quality of matches will be deteriorated, since you will be under or overrated by an amount (not big but stlll).
This third point has an important part, the more you go against what the system predicted (long winning streaks), the more your MMR will fluctuate, because it no longer has an accurate data of yours (you improved in comparison of others). This make so that improves or lose in skill (or build power for example) will be more easily sized by the system (anyone with more than 4-5 winning streaks will notice an additional 1-3 points win of skill rate per win until he start to setle again).
MMR in season 1-4:
A common mistake people do its compare the old seasons with this one, there are several difference:
First one: The matchmaker had two mayor problems in previews seasons:
- Pip restriction to search for opponents of the same MMR (in all 4 seasons).
This produced teams with very different compositions of MMR and can only happens now in very low population hours and in extreme MMR values, like 2000 and 400 (900 its not an extreme value).
- Matchmaker different formula (season 2-3): Of 10 people it grouped the best 5 MMRs in one team and the worst 5 in the other.
This isnt happening now, can happen that a team has a general better MMR but not that all the best skill ratios are in one group.
Second: No checkpoints, this isnt grind based where you could get to one point, tank (knowing you were doing it or not) your MMR thanks to the checkpoint and fight against the low MMRs guys in the division.
In this season you tank your MMR, you lower your division and fight against guys of similar MMR than the one you have at the moment at each MMR value, as such you tank and lose progress to come back against the same foes.
Third: All people start in the same division or there were 3 points to start (emerald, amber and saphire), now each people start at half the difference between their MMR and 1200, so your starting point depends of your pre soft reset skill rating.
This means no low level skill player its suposed to start in platinum in the long run (since its a soft MMR reset, there was still some of the old leagues MMR distortions, so it could happen this time).
Four: Thanks to the 3 first factors, in previews leagues you could be in legendary division and have a 900 skill rating (been in the worst 50% of the population in terms of skill).
Now if you mantain legendary, you are really on that level.