Standings on the Rankings page are ordered by TrueSkill rating, a system developed by Microsoft that is used for many games on XBox Live and PC. The TrueSkill rating is based on a complex mathematical formula, but here are the basics:


The TrueSkill system works on two basic values, a team's uncertainty value and their actual skill.


The TrueSkill skill rating functions similar to other rating systems, like the Elo system in chess. In general, winning games raises it and losing games lowers it. However, it also takes strength of opponent into account. A highly-ranked team that beats a low-ranked team may see a very small increase in skill, whereas if the lower-ranked team upsets the higher-ranked team, their skill may increase substantially.


Where TrueSkill differs from other rating system is by taking uncertainty into account. The uncertainty value is how the formula accounts for luck. Teams that consistently beat other teams ranked above them have low uncertainty, whereas teams with inconsistent results have a high uncertainty. The more teams play, the more accurate their variance becomes, and the less their uncertainty has an effect on their total rating. This allows TrueSkill to accurately predict ratings, even for teams that have very few games played.


Note: TrueSkill does not take game point differential into account, only wins and losses.