Shoreline wrote:Maybe that is why there is so much sandbaggers at IGS claimed by others, IGS people gave up on proper ranking and just play at improper kyu level. It may be the fault of slow ranking adjustment rather than the sandbaggers themselves.
IGS ranks actually respond a bit more quickly than has been described here. In the first 20 games, your rank is provisional, and it adjusts every 5 games. After that, your rank increases (decreases) a half rank for every 5 net wins (losses) between 17k and 12k. So, if you start out at 17k, wins 6 games and losses 1 (assuming properly handicapped games), your rank will go up to 17k+. Between 12k and 7k, it takes 6 net wins.
In my experience, slow adjustment does not explain the inconsistent ranks of opponents. I often check the rank histories of opponents, and it is fairly common for players to be playing 2-3 ranks below their highest ranks. Obviously, people's ranks fluctuate, but some of these patterns seem quite suspicious. See here for a particularly egregious example:
viewtopic.php?p=216570#p216570.
Plus, I'm sure that anyone who plays on IGS has experienced players who resign after having just been matched, having just played the minimum 2 moves necessary to establish a game as official, or having achieved a decisive lead. When someone resigns an auto-matched game, the system penalizes the player with half the value of a loss. So, if one wants to lower his rank by a half-rank, one simply needs to resign 10-12 games immediately after being matched. During a busy period, that would not take very long.
I really enjoy playing on IGS, but this is the one problem that I wish they would fix.
EDIT: In fairness to the IGS staff, I should also note that it is not at all obvious to me how one could easily fix this issue. Even a policy like removing accounts that clearly manipulate their rank wouldn't work because banned users can easily just create new accounts.