Do you have a link to the longer winded discussion of how matchmaking works and/or how you determined it? There's a few people that have been debating about it and trying to figure out how it works (and what seems to be broken about it) that would probably like to be cued into it (off the top of my head,
@97Stephen ,
@Zombie Aladdin ,
@Holidaze ,
@jsilva , ) That sounds like what we were thinking.
Sauce and
sauce of sauce
The first is a translated summary of the second.
As for how matchmaking in general works,
here is an overview of how Microsoft's TrueSkill algorithm works. Warning: it is very long and Math heavy. Still, it's an interesting read if you really want to get an idea of how matchmaking works.
Here's a layman's summary. The game calculates your skill based on certain variables (k/d, w/l, shot accuracy, how many times you defuse the bomb vs let someone else do it, etc). It then looks at whether you win or lose consistently, or whether you bounce between wins and losses to establish a standard deviation (how uncertain the game is that you will win regardless of your skill level). It then assigns you both a skill variable (mu) and uncertainty variable (sigma).
The game then calculates a "skill chain" (beta). It takes every member in the lobby and arranges them from best to worst based on their mu. It then calculates how many points it must add to your mu to give you an 80% probability of beating the least skilled player (who has the lowest mu). Low beta values means a more evenly matched game based on player ability because the game has to add less points to gain the 80% probability. A high beta means luck is a bigger factor because the game had to add more points to reach 80%.
The game also calculates "partial play:" the amount of time a player was active during a match. This gives the game an idea of whether someone played for the entire match or just stood there.
It then takes all of this information, plugs them into complex formulas, performs several marginal calculations to get other values to plug into these formulas, and eventually assigns a team performance value to the players grouped together. The game then subtracts these two values to determine the probability of one team beating the other. With that established, it then determines how much a player's rank should increase based on whether the win was expected, slightly unexpected, or very unexpected (an upset win). This is the "K factor" from chess: it determines how much a win or lose impacts a player's rank. An upset will result in a higher K factor, thus a greater change in your rank.
Side Note: I suspect this is why S rank is so punishing. The algorithm may consider any loss by S rank to be unexpected or an upset, thus a heavier loss in points.
Anyway, this K factor also updates a player's mu. An upset win will cause a higher jump or drop in your mu value. These changes become less dramatic the more matches a person plays. Someone just starting out who destroys the competition will have an almost vertical spike in their mu. Assuming Splatoon uses an algorithm like TrueSkill, this can explain why so many experienced players who start alts get grouped with competitive players. Early in the game, this can cause dramatic shifts in the caliber of players you face. Many talked about starting new accounts and only getting to play a few games before getting thrown in with very competitive players. This is probably because the kill or coverage variables in your mu cause it to jump to a specific range where the game considers you S tier in those areas even though you just started playing. Ranked limits the speed you can make this jump with the points system to prevent people from jumping straight to S rank from the get-go, but TW probably doesn't have this "safeguard."
What does all of this mean for Splatoon? In looking at the cited source, it means that your mu is weighted such that kills, deaths, and coverage points result in more drastic changes than other factors (like wins and losses). The game probably flags certain value ranges as "high kill," "high death," and "high coverage." If you're borderline, you may bounce between those value ranges and randomly get matched up with two very different types of players.
This is all hypothetical of course I don't know if Splatoon uses a derivative of the TrueSkill algorithm or uses the more primitive "dueling heuristic" Elon method where it considers two teams as one player vs another and compares their bell curves. With that said, this does fit with my own observations. When I get a good kill streak going, I find myself playing more aggressive teams. When I play passively, I find there are more players who are also passive. Ymmv though.
