Thanks for the report. I've passed it along to the matchmaking team to dig into and will let you know what they find.

Because skill, and corresponding matchmaking rating, is individual and each person has a different starting point.

To phrase it in a more obvious way, if you put a player who is bronze tier skill in the same placement games as a player who is master tier skill, after the games, they're still different skills even though they had the same record and same opponents for the placements. They're not both suddenly platinum tier players.

The initial seeding cap hasn't changed.

Not necessarily. Ranked tiers in Heroes are based on the individual players skill so two players of the same rank are going to be of similar skill as well.

One of the challenges of MMR based on straight wins/losses in a team-based game is that the reason for the win/loss is basically evenly attributed to the team as a whole. So, if the system knows one player is bronze tier and the other is master tier to start, it has to assume that they both contributed according to their skill. If those players only ever play games together, its impossible to differentiate the individual performance from them as a team so they'll gain/lose rank at roughly the same rate.

If the players are playing other games apart from each other, though, then there are other variables in the equation and the individual's performance can be more easily teased out.

Pretty accurate. It's a fairly standard system based on the core assumption that, all other things being equal, if you are higher or lower skill than everyone else at your current ranking, you are the X-factor that causes you to win/lose more games.

It works, but the downside is that if the skill difference is pretty small, it can take a lot of games for the effect to be felt.

If you wanna send me the battletags for the folks, I can ask the team to look into it. It's hard to say without pulling actual info.

I'd love to understand how you arrived at that conclusion. In that example, there's two different people of wildly different skill on the team. Do you suggest they should be placed at the same point anyway?

To follow up on this, the placement was an interesting combination of things.

First, you had a lot more games in QM than UD, but there was enough data in both QM and UD for the system to consider both valid choices to seed from. In that case, it uses UD as the seed since its more indicative of the play environment for ranked than QM is.

Interestingly, your QM MMR is significantly higher than your UD one. Your QM MMR is master tier. UD is diamond. Both are above the placement cap of Plat 3, though, so that ends up not mattering much. What did matter, though, is that your uncertainty in UD was still relatively high since you don't have a ton of games played there so, since that was used for the seed, your uncertainty coming into ranked was correspondingly high.

Then you won the first 6 games against high-skill teams, which bumped your MMR back up significantly due to the high uncertainty. Going 2 and 2 for the last 4 still left you with master tier MMR at the end of placements. It's not as high as your QM MMR, but a bit higher than your UD one.

There's nothing inherently wrong with placing into Master as long as you're a Master-tier player, so the question then becomes: are you actually a Master-tier player, as indicated by at least your QM performance, or is it a fluke of the system? As you continue to play ranked, it should become apparent which is the case.

Either way, this case was really useful to dig into and there are a few places along the flow that we may adjust things to improve the outcome in the future. Thanks for bringing it up!

You have to be careful with anything that is artificially imposing limitations on where someone is ranked. Because rank is the only visible indicator of skill and people react allergically to folks of different ranks being in the same game together, even if they're the same skill, the matchmaking system prefers to match people of similar rank together. As long as their rank is appropriate to their MMR, that's a non-issue, but if they diverge too heavily, it causes problems.

That's part of why we got rid of the Diamond 3 cap. It worked fine at the start of a season when there were a lot of higher MMR folks at the cap, but as the season went on and the higher MMR players moved up to master, the system had a harder time making matches for people who were higher MMR, but joined later in the season so didn't have that large pool of other, similar players to be matched with.

The fix for this is making MMR visible, then decoupling MMR from rank entirely (and yes, that's on my wish list to do). At that point, we have a lot more freedom with rank without affecting matchmaking quality.

You missed a key requirement: being a master-tier skilled player.

Without that, it doesn't matter how much QM you win. You're going to seed in at mid-Plat at the highest and if you can't hang at that point, you're not going up in rank.