[quote][b]Posted by:[/b] thurst0n Not sure if someone has asked this before. But according to your equation it should be impossible to level up after a loss. Why then did my friend. Who I know had a very high sigma. Level from 4 to 5. After playing team doubles with me. I think I was around 40 at the time. Game 1: http://www.bungie.net/Stats/GameStatsHalo3.aspx?gameid=176038835&player=Blebbins Win Level 1 - 4 Game 2: http://www.bungie.net/Stats/GameStatsHalo3.aspx?gameid=176044027&player=Blebbins Loss Level 4 -5 Game 3 http://www.bungie.net/Stats/GameStatsHalo3.aspx?gameid=176049375&player=Blebbins Loss Stayed Level 5 Maybe I am missing something. We got creamed in game 2 and he still leveled up. The game before We won and he leveled from 1-4. I just don't see how he could level up after losing according to your method?[/quote]The formula given is the formula used to determine your displayed skill level (the one you see next to your gamertag). Your skill level is a conservative estimate of what the system thinks you might be. So the formula is this: [b]"Displayed skill level" = Mu - K*Sigma[/b] Mu is a number tracked behind the scenes and represents the skill level the system currently thinks you might be at. Remember the displayed skill level is not the same as Mu. The displayed skill level is a conservative representation of Mu and is calculated using the formula above. Sigma (aka. certainty) is the variation. If you have a Mu = 25 and Sigma = 5 the system believes you are in the range of 20-30. K is a constant and is assigned by the developer. Microsofts documentation says 3 is often used. The higher the number the more conservative the estimate. So in a case where Mu = 25 and Sigma = 5 the displayed skill level would be = 25 - 3*5 = 10 If sigma drops the displayed skill level will rise. If Mu drops the display skill level will fall. When you lose a game Mu always goes down, however, if Sigma drops enough from that loss your displayed skill level can actually rise. [quote][b]Posted by:[/b] thurst0n One other thing. Do I have a differant sigma/mu for each hopper? (TS, TO, Tact, Doubles, Lone Wolves?) Or is my sigma the same for everything.[/quote]Every playlist is seperate so you have a different Sigma and Mu for each.