Understanding the score shown on profile

[shinuito]

Some relevant quotes, threads

~2017 Glicko2 system

@anoek

During our analysis we’ve seen that players whose ranks are less than 25k are very difficult to adequately rank in the sense that handicaps at that level are not a reliable way of accounting for strength differences. As such, we’re now only assigning ranks to players who are strong enough to play with handicaps, which seems to equate to being about 25k and above. The only real effect of this is that when two players whose’ ranks would be less than 25k play each other, they will play without a handicap.

@anoek

Handicaps will no longer be enabled by default for any automatch games between players whose rank is less than 25k. When matches are made between players and one player is above the 25k threshold, the handicap will be computed as though the other player was 25k. This is not retroactive.

~2020 Glicko2 analysis

@anoek

Does it make sense to use ranks below 25k?

Mostly focusing on win-rates with handicap stones.

@anoek

That being said, it’s not all that bad, and there are some benefits to having those ranks beyond strictly correct functional computation of handicaps, namely so people can see their progress. I don’t know that we should go any lower than 30k, but we might very well bring back ranks down to 30k just so people don’t feel like they are perpetually stuck at 25k. We may still stick with just not giving handicap stones automatically to players in that range, or reduce how many are given, but all of that are things to determine later.

~2021 updates

@anoek

Along with aligning our low dan ranks, we want our ranks to be as useful as possible. One rank difference should equate to being a one stone handicap difference on a 19x19 board, regardless of what rank you are, or the rank difference. While our old rating to rank formula achieved this for a decent percentage of the population, it was not adequate in the lower ranks, and instead placed a notable percentage of our population into a perpetual 25k rank. So, we ran a whole lot of simulations with our entire game history to came up with a better mapping that aligned our ranks well, gets rid of the 25k problem, and produces fairly consistent handicap win rates across the board.

You can see what I mean that a lot of the focus is on aligning rank and handicap.

I think this was an update that gave lots of players a bump in rank, so it might’ve redistributed ranks a bit more.

Since then we’ve also had the pick your starting rank update. I’m not sure what the impact of that has been on any of the analysis.