2021 Rating and rank adjustments

[yebellz]

Sorry, I have only barely skimmed this thread, so it might have already been discussed, but I just wanted to note that @S_Alexander created another thread looking at how people’s ranks changed here:

New Ranks vs Old Ranks, Who Got What

Since both rating formula and ratings themselves changed, it’s interesting to see how ranks changed. I polled a bunch of active players. So linear. [image] Roughly like this, from linear fit new_rank = 0.75459341 * old_rank + 9.00910366 So at 30k we get 9 stone boost to 21k. And at 7d we get no change at all. And at stronger 9d ranks it means their ranks get a little more difficult. The ranks get a little bunched up, so with the same strength difference you’d give less handicap stones with …

Here is another visualization and some observations

@yebellz

A few observations…

1. Old ranks from roughly 26 to 35 kyu have effectively been reinstated, but given a big boost to now be viewed as at least 25 kyu
2. The new TPK (20+ kyu) ranks were completely off the old scale
3. The adjustment slope of ~0.75 reduces the amount of handicap stones used. Two players that formerly played with 4 stones would now only use 3.