What determines MMR?

Hush up and take advantage of the freelo baby.

Have you gone on a massive losing streak? That lp gain/loss situation is when your actual mmr is lower than the mmr of the division you're in.

MMR is determined by wins and losses

The system doesn't always place both teams with people right near the same MMR

MMR isn't based on skill, its whether you get good teams and win or shot teams and lose.

incredibly wrong answers all around.

MMR is based off several things, not only wins and losses.

Gold per minute Amount of wards used per game Amount of wards killed per game KDA CS Your personal KDA v the amount of kills your team has (kill participation) Assists on objectives(drags, barons, rift harold, towers, etc etc.)

Basically, did you help your team succeed? Did you play as a team player?

If it was based 100% on W/L ratio it'd be pretty absurd. Not that W/L ratio doesn't play a big role in it as well.