Is MMR calculated only on a personal performance like the new mastery system does? So say out of my promos I lose all 10 games but my average (as support) was 1/3/15, would I be placed automatically in Bronze because I lost all my games or would it only account for my own score, regardless of how my team mates performed?
example: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1828922860/219122358?tab=overview
There are a number of factors here. Please note elo=matchmaking, and you can't see what people's elo is. Elo is hidden behind the league system.
The relative difficulty of the match. If you are 1500 elo in a game where the average of both teams is more like 1400, then you will lose more points if you lose, and gain less if you win. This is how your matchmaking changes are determined. Games are matchmade based on elo, not League division.
Your elo changes are further adjusted by 'volatility', another hidden statistic. The higher your volatility, the more elo you gain or lose per game. League points also have their own separate volatility. Players who just began ranked for the first time of the season have the highest volatility. It will only decrease after playing 50+ games.
Provisional games, unless duo queued, will always draw from the pool of provisional players queueing. However, some of their elo remains from last season. Though it will avoid it, you will often end up in games with Diamond elo players fighting Bronze elo players because of the limited pool.
League point gain or loss is determined by the difference between your elo and your league. For instance, if you are bronze 1 league with gold 1 elo, you will gain extremely large amounts of LP for winning, and lose under 5 for losing.
So in summary, to answer both your questions:
Your score ingame doesn't matter, only if you win or lose. However if the game is mismatched and you are in a match with weaker opponents versus stronger ones, you won't lose as many points for losing that game.
Placement after provisional games is dependant on their hidden elo, not their ratio of those matches being won/lost. Someone who started at 1700 elo might lose 8/10 games and end up at 1400 elo, then be placed in gold. Someone who started at 1200 elo might lose 8/10 games and become 900 elo, and be placed in bronze 5.
kda doesn't affect mmr, no. winning and losing does, as well as duoing with someone. If you win, it goes up, if you lose it goes down.
Win's and Loses + Opponents MMR.
it used to start everybody at 1200 elo and +50/-50 every loss/win for 10 wins, then lesser gains and losses eventually to +12/-12 elo
cuz of previous seasons they had high mmr
just don't worry about it and win more than you lose
