The Quint^ effect is observed when Quint^ plays solo on XBOX Live.  It is believed to be a side effect of TrueSkill ranking system.

While playing solo Quint^ dominates his competition.  This stands in stark contrast to his performance while not playing solo on XBOX Live.

While there is generally no concrete evidence of the domination, it is believed that this may be possible because of TrueSkill.  TrueSkill with only Quint^ to match with ends up "setting the bar low" which puts Quint^ against the lesser skilled players on XBOX Live.  In this scenario, it's easy to see how Quint^ may be able to dominate. 

While playing with the collective, Quint^'s TrueSkill rank is only part of the matchmaking equation.  Due to the superior skill of those he plays with, matchmaking tends to be biased above Quint^'s skill level.  As a result, Quint^ does worse while playing with the collective.