Xbox Live TrueSkill System

I have heard a lot about the new XBOX 360 Trueskill ranking system, and decided to try and find out a bit more about it. After jumping 10 ranks after coming second in my first race of PGR3, my ranking up has slowed significantly. I wasn’t sure how this process worked, but I know now, and here it is for anyone who is interested.

All XBOX 360 games use the trueSkill Ranking system. This serves 2 purposes. It tugs at the competitive nature in all of us to get better and better, and thus actually see our ranking increase, and it enables better and fairer match making for multiplayer games. Playing against people much better than you, or much worse isn’t that much fun. No one likes just getting shot up all the time, or only seeing your opponents in a racing game up to the first corner before he leaves you in the dust. If possible, the TrueSkill system will match you up with people close to your own ranking, which should result in some good gaming.

From what I believe, there are 30 levels in the Trueskill system. When you first start playing a game, your level will be 1. Some games show your level in the game’s lobby. Level 30 means you are a machine, and nobody must mess with you. The system that determines your ranking uses 2 numbers to get to it. The first number is your actual ranking, which is 1 when you start. The second number is the systems certainty of your ranking, which is kind of inverted, meaning a high certainty variable means the system is not very certain of you. Let me explain it via an example. You have just loaded PGR3 for the first time. Your Ranking is 1, which is the lowest. The system has no idea how good you are though, since it is your first race, so the certainty variable is high. Lets assume you are Kimi Raikkonen and you win your first race. Because your certainty variable is very high, you will jump many ranks and now you may be a rank 8. You win your next race also, but now the system is a little more certain of you, so you only jump up 5 ranks, to level 13. Your next race, some idiot takes you out early on and you finish 7th. Your ranking will go down quite a few places, since your certainty variable is still high. You may now get to rank 9. As you race more and more, your certainty variable gets smaller and smaller, as the system gets to “know” you. After 100 races, you may be ranked level 20. If you win a race, you won’t rank up very much since the scope for ranking up is smaller because your certainty variable will be much lower. The benefit of this is that a single game won’t effect your ranking very much after you have been playing for a while. A bad loss or a lucky win won’t change things much. If you are consistantly winning against players of a similar rank, you will rank up, but fairly slowly, and likewise if you are consistantly losing.

It’s a good system, and although I wish my rank was higher, I need to consistantly win races to get there. I hope this explains it in a simple way. The people who designed it are hardcore mathematics guys who deal with complex statistics etc, which is a bit beyond me, but at least this should shed some light on the subject for those who are a bit confused as to how it works.

-EDIT- There is a lot more information (which is a lot more technical) now available at the Microsoft Research Trueskill Website.

6 thoughts on “Xbox Live TrueSkill System

  1. Caleb

    You seem to know alot about the ranking system, so I thought that you might know where I could view it at. I ask all around in CoD2 but noone knows and we all play ranked games all the time and have no idea of our rank.

    Reply
  2. Duncan Post author

    Hi, thanks for the comment. The Trueskill ranking system is used for background matchmaking. Each game presents it differently. PGR3 shows you your level, but some other games don’t. I know COD2 doesn’t. Maybe they will for COD 3. Also, remember that the term ranking is a bit weird. It uses it to match you will similarly skilled players. If the game doesn’t actually use a leaderboard like PGR3 and GRAW do, then seeing your ranking is pointless since it’s just a number without real context. Hope that makes sense.

    Reply
  3. phirephight

    I noticed you mentioned PGR3, but I was wondering if you could elaborate on how the GRAW ranking system works? Thanks

    Reply

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