Glicko

I said earlier that I wouldn't be assessing the Glicko rating system because it was basically the same as TrueSkill, so I didn't expect significantly better performance than TrueSkill.  That hasn't changed, but I decided to take a look at Glicko anyway, mainly because I've become intrigued with the Whole History Rating algorithm from Rémi Coulom and that led (indirectly) back to Glicko. I haven't yet wrapped my head around WHR (and may never do so -- the math is difficult) but I was interested enough to code up the Glicko algorithm.

I won't attempt to explain the Glicko algorithm -- it's described in detail on Mark Glickman's website -- but just jump into the performance.  My implementation recalculates a team's rating after every game -- the same as done with TrueSkill.  There is very little to tweak in Glicko, so here's the basic performance:

Predictor	% Correct	MOV Error
TrueSkill	72.8%	11.09
Glicko	70.8%	11.71

As with TrueSkill we can hack an MOV-based factor into Glicko and improve our accuracy somewhat:

Predictor	% Correct	MOV Error
TrueSkill	72.8%	11.09
Glicko	70.8%	11.71
Glicko + MOV	71.8%	11.56

Even so Glicko isn't a competitor for "best of" the rating systems.