Hi, I have noticed the rankings of bots have shot up during the month of April. Seems like KGS is adjusting its ranking in the inflationary direction, closer to other popular servers, like Tygem.
One reason I could think of, is that users in KGS have declined, and KGS admin is probably trying to lure players with higher rankings. The reason why I thought so is that it is a prevalent business practice in Japan, and go salons which rates you with a higher dan/kyu attract more customers.

Or maybe they simply anchored the wrong players.

Maybe the bots really got stronger. Maybe it's just "noise."

I have recognized another ranking adjustment, I was pushed up by one rank overnight, I was stronger of the rank, but there were someway to go before crossing the rank border. I recognize a similar thing occuring in other players, they were stronger in their respective ranks but got pushed up by a rank this morning (21st Aug, Asia time).

Something is going on, but I wonder if it might be an error. I was 5k last time I played, but just logged in to find I'd been promoted to 4k.

But the rank graph says I should still be 5k:



Is this what it looks like when they change the anchor players? Or maybe there some other change being made?

Did you give it a full day to update?

There was nothing to update. I haven't played on KGS for at least a week or two.

This doesn't mean that your rank is not recalculated.

_________________
North Lecale

Look here

http://gokgs.com/graphPage.jsp?user=Blindgroup

and zoom on the right. The line is almost vertical.

Ah, yes. Seems from posts on r/baduk that they may have indeed adjusted the anchors yesterday. I'm surprised that KGS did not provide a notice to players on their website or something. Might have avoided some of this confusion.

When people discuss the KGS ranking system, some often have beliefs that I suspect are mistaken. So, I don't know how accurate the conclusions on r/baduk might be.

But, in this case, the ranking bumps seem to be widespread: From KGS chat, it was noticed several times Monday. The most reasonable explanation does seem to be a change in the anchors.

But, not all such changes are intentional. A few times, when things like this happened in the past and when Glue was superadmin, she told us, after looking into it, that some anchors had quit playing or some had become unstable. After these discoveries, she changed anchors, which would undo the rank bump.

I also noticed a change in my graph and I think every other player. A big bump, around 0.5 rank.

the graph on KGS server is also delayed compared to the graph on the KGS site, around 24-48 hours delay.

In the past, it already happened and generally there was a big correction of the ranks a few days or weeks later. I hope they will soon fix the delay between the graphs...

I would like to know if it's intentional or not. However it is not such a big change and the ranks seem still valid compared to others servers.

There was another rank adjustment, around one sixth of a stone around 30 September, 2018. This time, everyone, including the bots, was pushed downward. Taken together with 0.5 stone upward adjustment on 20 August, everyone should have been pushed up by one third of a stone, or 0.33kyu/dan.

By the recent rank adjustment (mid-January 2020), the accumulated ranking adjustment since the beginning of 2019 (both up and down) seems to have amounted to a full-stone upward adjustment.

This probably means I have to take a full stone off my current rank when comparing it to my pre-2019 rank. Also, I would have to deflate my current rank by a full stone if I want to compare it to other servers, such as on;
https://idex.github.io/go-rank-survey/g ... mean-ranks

Not necessarily. Without the adjustments, the ranks might have drifted downwards.

Yes, KGS rankings seem to be pretty far off, and have not been closely tied to appropriate anchors in a very long time. I am trying to gradually tweak the system, without making major shockwaves. Our goal would be for KGS ranks to align more closely with AGA ranks. There are so many servers, and such wide rank variations among them, that picking a standard is very hard. The merit of AGA ranks is that we have extensive records of in person play for hundreds of individuals.

If you find your rank, or someone else's has changed in a way that is totally irrational, let me know here. I can't promise to fix anything, but my actions may cause unintended fluctuations, and knowing about them can help me to make better decisions in the future.

_________________
Paul Barchilon,
AGF Vice President
KGS Manager

As you're working on aligning the KGS and AGA rating systems, I'd like to point out some critiques to the AGA rating system and other rating systems: see https://wismuth.com/elo/calculator.html in section "Elo per stone in go". I think the author has some valid points there.
(I'm currently in a commission that scrutinizes the EGF rating system and I happened to stumble on that page.)

Do I understand correctly from the graph of the above link that, around EGF GoR 1500,

• 1 EGF rank difference corresponds to a strength difference of about 2.5 stones
• 1 AGA rank difference corresponds to a strength difference of about 5 stones ??

That's hard to believe.

That's not really what it says.
Elo is only about winrate, not about ranks or handicap.
GoR is also about winrate, but intended to be adjusted for handicaps (that's why the green line is curved).

So it says around 6k EGF (= 1500 GoR)

• In reality (multicolored lines, blue line), 1 rank difference corresponds to about 55 Elo difference = 58% observed winrate
• In EGF system (green line), 1 rank difference corresponds to 100 Elo difference = 64% expected winrate
• In AGA system (red line), 1 rank difference corresponds to 250 Elo difference = 80% expected winrate
• In KGS system (table below the chart), 1 rank difference corresponds to 50 Elo difference = 57% expected winrate

So if you compare the different systems:

• around 6k EGF (= 1500 GoR), the KGS expected winrates are closer to observed winrates than than EGF and AGA.
• around 8d EGF (= 2800 Gor), the EGF and AGA expected winrates are closer to observed winrates than KGS

So KGS is best for kyu rank gaps, AGA is worst. For top amateurs, EGF and AGA rank gaps are better than KGS rank gaps.

250 is about 5 times 55, so doesn't it imply that 1 AGA rank difference amounts to 5 stones?

No, 100 Elo means 64% winrate, not 1 stone handicap, except around EGD 1d (= 2100 GoR) where the observed winrate for 1 rank difference happens to be about 64% = 100 Elo.

You cannot add or multiply Elo rating differences to add or multiply winrates. It's not a lineair relationship (it's an s-curve as shown in the first chart on that page).