I won a ladder game by timeout (1d vs. 7k), but I lost one rating point after the game. (2141 to 2140) I figure the cascading factors of timeout and wide rank discrepancy caused it, but winning should never decrease rating, obviously.
hmm, this is something we saw a long time ago and I reckon it never got fixed. Iâll check into this to see whats up. In the meantime Iâll correct you up by one point. Sorry for the trouble!
Sounds like a rounding error. Nothing to worry about in my opinion.
It seems the problem wasnât fixed and it isnât rounding problem since I had 1958 points before my win by 10.5 points against 16k (Iâm 4k), and now I have 1956, so 2 points loss on a clearly winning gameâŚ
First of all, the rating system changed since 2014, therefor your problem has nothing to do with the initial problem of this topic. Please open a new topic next time if the last post in a topic is ancient.
And in the new rating system, your rank can drop by some points after a game, since the rating system calculates your rank by looking at your up to 15 last games. If the rating of one your opponents changed in between, your rating can drop, even if you won the last game.
The math of the ranking system is somewhat arcane. Therefor I donât explain it in detail here. If you really like math, send me a message and I provide you detailed information.
Hello flovo, You have an interesting point on this topic and I was wondering if it would not be too much trouble to send me those mathematical statistics, no rush or worries if you canât do it though!! I am just curious because I want to learn more about the rating system and I should be able to figure out the math with a little thoughâŚ but again, only if it is not too much work for you!!
Thanks Regardless from the âGoBoardâ (@_GoBoard)
You can read the math behind Glicko2 here http://www.glicko.net/glicko/glicko2.pdf
And this is the post introducing Glicko2 on OGS. It describes the OGS specifics.
Have fun with it
Thanks for the info pal!! I am very curious about these types of things!!
Wouldnât it be simply posisble due to rank recalculation thatâs implemented in OGS version of Glicko? Up to 15 or 1 month (iirc) most recent games are still âwarmâ and their contribution to rank is reevaluated every time a new game is finished. In particular that means that if your opponents ranks dropped in that time you can experience a drop just due to this recalculation.
And btw. how do you ever notice a drop like that?!?
Yes, quite probably. I think thatâs what flovo was implying in his original comment.
To put it âsimplyâ a victory against a 12 stones weaker player is very insignificant. It of course does not worsen your rating, but there is almost no notable boost to speak of after such victory.
However after each finished game the system also recalculates your rating based on how a set number of your previous opponents are doing. Meaning if you have won against a stronger player who then proceeded to lose several ranks the system may actually take some points away, because said opponent was probably not so strong to varant such a big boost. (Hope that makes sense )
I have also experienced a rating drop after a win, but it seems it was a bit of a different case from the ones that were shared before, as there was a relatively small rank difference (11k vs 9k). My rating drop was somewhat more significant as well (11 pts Glicko, 0.2 kyu). Out of interest I took a look at the ratings of my last few opponents and they all seem to have been quite stable; none of them changed more than 2 kyu, anyway. This is a relatively new account Iâm playing on, so perhaps that has something to do with it? Iâm more curious than anything else at this point, although not quite enough to sit down and do out the math off that paper flovo posted.
I donât know whatâs the reason for the drop. As far as I can tell your rating shouldâve gone up after that game. It was your 16th ranked game, so it should be the first game of a rating period (earlier games should have no influence on your rating at this point).
Huh, interesting. System glitch perhaps ÂŻ\_(ă)_/ÂŻ
Same here  won by timeout and dropped 0.1 k
I mean I dont care that much about rankâŚ but if you play a match for months (against a stronger opponent when the match started btw)âŚ it really seems you are going to win, then (s)he times out and you drop in rating despite your winâŚ feels a little dissappointing tbh! My last opponents didnt change that much in rank, most of them climbed a little as far i can tell. I am not a mathematician so a simple explanation for this would be much appreciated!
BTW, would this have happened if I won the game regularly?
Absolutely the same thing. The timeout had nothing to do with your final rating.
There are three possible explanations for a rating drop after a win:

Your rating was in âpreliminaryâ status, and was going to drop anyhow, due to recent adjustments of your recent opponentâs ranks. Your win just lessened this. This cycle of adjustments happens all the time.

Your win happened in the same batch as a loss, and the loss outweighed the win

A bug.
So far, it has always been either or both of 1 & 2 when this is reported.
Thanks for the quick reply. Just out of curiosity, is there anyway I can check if possibilities 1 or 2 are the case?
#2 is easy to check: mouse over your rating graph for the date when you won the game, and it will show you how many games are bundled in that data point.
#1 is much harder to check retrospectively. You can get an indication by looking to see if your recent opponentâs ranks were trending down at that time.
hmm okay, the graph isnt updated yet but for all other timepoints the âbatchâ consists of 1 game only, or am i reading this wrong?
concerning point #1: as far as i can tell some opponents got stronger, some weakerâŚ
again, thanks for your input though. It is only 0.1 kyu so its nothing to break a night of sleep over it, i just want to understand how it works
Me too  and find bugs if they exist. Can you point out the game in question?