Yes. It only works when teams of 4 get matched up with teams of 4.
First let's learn how people manipulate TrueSkill.
TrueSkill assigns an individual rank to a player in a playlist based on the player's game history in the playlist. When that player join 3 others, the team is given a rating, which is more or less an average of all of the players' game histories. Before a match begins, TrueSkill predicts a winning team based on which team has the higher average rating (this is NOT their visible TrueSkill ranks averaged out). The predicted loser goes up a lot in TrueSkill if they end up winning, and don't go down much for losing. The reverse is also true: the predicted winner doesn't go up a lot for winning, but goes down a lot for losing. Derankers/boosters lose games on purpose by themselves and rejoin their team so it brings down their rating a ton. This helps ensure that they become the predicted loser every game. They consequently maximize all of their wins and minimize all of their losses. Boosting.
What does LoL do? When it comes to playing a full party, they simply don't average out the players' individual ranks. They go in fresh.
Imagine this team of 4: Bob, Fred, John, and Tim. Tim leaves to lose a bunch of games on his own and then rejoins his teammates. Let's see what would happen with the different ranking systems.
TrueSkill: The average rating of the team goes down a ton. They now have a very high chance of being the predicted losing team. Tim is their booster account.
LoL: Tim's individual rank isn't factored into the team's net rating. His deranking was a complete waste of time. The rating of Bob, Fred, John, and Tim are dependent solely on the games that they all play together. Yes, that means if any one of them is replaced with another player, they will receive an entirely new rank.
In LoL, a 5v5 game, they have two ranked playlists: A 5v5 playlist called Ranked Teams where you have to go in as a team of 5 and every party you go in with has their own rank, and then there is Ranked Solo/Duo. In Ranked Solo/Duo, you can either go in with a partner or by yourself. However, the ranks will be separate. Just say Tim chooses a partner from his team whenever he feels like playing this. This means that [Tim, Bob], [Tim, Fred], and [Tim, John] all receive separate ranks. Oh, and of course [Tim] by himself receives a separate rank as well.
FAQ:
I have a ton of friends. Does this means that I get a new rank for every single party combination that I make? That's freaking lame.
Yes. It's not as bad as it seems. If anything, it promotes the idea of forming a solid team and constantly playing with each other to get better. Also, this is the sacrifice of having a working ranking system.
So I'll have to work my ass off every time I make a new party combination to reach a high rank?
Well, LoL doesn't start you off at level 1 like Halo 3's TrueSkill does. Assuming everyone is level 1 when they first enter a playlist is a completely stupid idea in the first place and I'm surprised I've seen very few people ever question it. LoL has placement matches so that you may skip a bunch of ranks. You will only have to work your ass off if the system doesn't have placement matches.
Wouldn't this segment the population by having separate playlists just to play ranked 4v4?
Actually, when you think about it, the Halo 3 Team Slayer playlist was actually two different playlists due to party restrictions. When has anyone ever gone in by themselves and played against a team of 4? Halo 3 Team Doubles was also two different playlists: a solo doubles playlist and a duo playlist. So this isn't an issue at all, really.
This sounds all great in theory, does it actually work?
In short, yes. Ask anyone who's played the game or simply play the game yourself. Really, the only way to cheat is to have two teams go on Skype and tell each other when they match up so that they can match up with each other. But come on, is there a way to prevent this in any game? Also it's not that effective since LoL has a ginormous population.
tldr: Individual rankings being factored into team rankings is a flawed system that breeds boosting. It needs to be canned.
Seems like placement matches could be easily faked. Purposely play poorly in them so you start off low ranked and then stomp on lesser players. No better than a really good player starting at 1 or an asshole purposely deranking. Nobody here has a solution better than actively policing griefers. I'm indifferent to visible ranks - I'll play a fun game whether or not they exist, whether or not griefers exist. But either way the game should have good skill-based matchmaking and constant policing of asshole players.