Edits to avoid people attacking me:
This is once you have established a stable rank by playing 15 ranked games.
The 15-game window this system works on leads to some quirks, like if a game you won against a stronger opponent just leaves that window, and is replaced by a win against a weaker opponent, your rank will go down, even if you won, and vice versa for a loss against a weaker opponent.
Sorry if I am just clueless or not understanding the chart, but how much would I move down if I lost to an opponent 900 rating differences above me? That should be my new strategy now playing the people I will barely move down against. All I gotta do is catch them in a tournament or ladder challenge them.
The ranking win change looks linear enough? I guess that it is linear, because it is increasing by one-two-one-two
The ranking loss change is probably going to be close to zero, so yeah.
To the extremes, let’s say a 400 Glicko point person https://avavt.github.io/gotstats/#/user/636788
Beat a 3150 Glicko point person (any of the 9 dans) https://online-go.com/player/624668/ (Note: he got affected by the correspondence disconnection bug - look at his rank before that), The 400 point person would (by a linear extension of the Win Rating Change - it might not be linear but it seems that way) gain 200 Glicko points, and the 3150 point person would lose 200, but they would still be a 9d! (Man pros are good)
The default rank of an unranked player is 1150. I don’t remember the exact averages, but I found the average rank is significantly higher than that. Assuming 60% of games are ranked, I found a (small) “compensation number” to add, so everything aligns.
looks up sigmoid function
What is the upper limit? (I know that sigmoid functions map numbers on the number line to a number from 0 to 1 - it is a curve (Side note: In a perfect world, a virus’s ahem COVID-19 ahem total cases would map a sigmoid function, with 0 being the bottom (or 1? It is a virus after all), and the total case number at the end would be the upper bound)). Based on my understanding, the function to derive the rank change would be a multiple of the sigmoid function, right? What is the maximum rank change? Edit: (this is not an edit - I just realized this) obviously the maximum would be double the middle, or 48! That doesn’t match up with your numbers though. Hmm…