Editing Xbox network (section)

===TrueSkill===<!-- This section is linked from [[TrueSkill]] -->
{{main article|TrueSkill}}
[[TrueSkill]]<ref>{{cite web|url=http://research.microsoft.com/osa/apg/details.aspx|archive-url=https://web.archive.org/web/20081210013829/http://research.microsoft.com/osa/apg/details.aspx |archive-date=December 10, 2008 |title=TrueSkill}}</ref> is a ranking and [[Matchmaking (video games)|matchmaking]] system which was first implemented as part of the Xbox 360's ''Live'' service. Developed at [[Microsoft Research]] [[Cambridge]] ([[United Kingdom]]), the TrueSkill [[Elo rating system#Other chess rating systems|ranking system]] is now used in over 150 titles for the Xbox 360{{Citation needed|date=November 2008}} and was used in the [[Games for Windows – Live]] game ''[[Warhammer 40,000: Dawn of War II]]''. It uses a [[mathematical model]] of uncertainty to address weaknesses in existing ranking systems such as [[Elo rating system|Elo]]. For example, a new player joining million-player leagues can be ranked correctly in fewer than 20 games. It can predict the probability of each game outcome, which enhances competitive matchmaking, making it possible to assemble skill-balanced teams from a group of players with different abilities.

When matchmaking, the system attempts to match individuals based on their estimated skill level. If two individuals are competing head-to-head and have the same estimated skill level with low estimate uncertainty, they should each have roughly a 50% chance of winning a match. In this way, the system attempts to make every match as competitive as possible.

In order to prevent abuse of the system, the majority of ranked games have relatively limited options for matchmaking. By design, players cannot easily play with their friends in ranked games. However, these countermeasures have failed due to techniques such as alternate account(s) and system flaws where each system has its own individual TrueSkill rating. To provide less competitive games, the system supports unranked ''Player Matches'', which allow individuals of any skill level to be paired (often including "guests" on an account). Such matches do not contribute to the TrueSkill rating.