Talk:Elo rating system/@comment-4484313-20111001135450/@comment-3014924-20111003074505

Because at which point you win is also important. You gain or lose more ELO at the start than later.

Player A may start with 5 wins and go up at 1400 (his real ELO), then play at 50% win rate for 30 games (at 1400 ELO, mind) then have a bad streak of 5 losses (about -60 ELO): Result: 20 wins, 20 losses, ELO 1340.

Player B may start with 5 losses and go down at 1000 (his real ELO), then play at 50% win rate for 30 games (at 1000 ELO, so opponents are less worthy than player A) then have a lucky streak of 5 wis (about +60 ELO): Result: 20 wins, 20 losses, ELO 1060.

Global: Same players win percentage tough different ELO. Player A better than player B.