Kotaku
Xbox Live's new, and very sweet, skill-tracking algorithm for ranking gamers:
μwinner ← μwinner + σ2winner/c * v((μwinner-μloser)/c,ε/c)
μloser ← μloser - σ2loser/c * v((μwinner-μloser)/c,ε/c)
σ2winner ← σ2winner*[1-σ2winner/c2 * w((μwinner-μloser)/c,ε/c)]
σ2loser ← σ2loser*[1-σ2loser/c2 * w((μwinner-μloser)/c,ε/c)]
c2 = 2β2 + σ2winner + σ2loser
Yes, it looks like gibberish to me too. But the trademarked ranking system, called TruSkill, is Microsoft's attempt at improving on Arpad Elo's famous ranking system used in Chess and many other things. The new system bases its score for a given player based largely on two things: the average skill of the gamer and the degree of uncertainty in the gamer's skill. It will take a much better man than me to truly explain the process, but it looks like Msoft is trying to rework the formulas to allow a player's individual improvements to more easily effect the skill score.
And here's another batch of gibberish (this one shows how matchmaking is done) to make what I just said make relative sense.
exp(-(μA-μB)2)/(2*c2)) * √d
c2 = 2β2 + σ2winner + σ2loser
d = 2β2/c2
TrueSkill [Microsoft Research]
