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Ranking - Consistency and One-offs
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Author:  judicata [ Sun Apr 25, 2010 11:35 am ]
Post subject:  Ranking - Consistency and One-offs
Question: how often is it expected that you will beat someone higher ranked than you/lose to someone lower ranked? I know there are a thousand variables here (what ranking system, what level, etc.), but just generally speaking.

Though I am still establishing my rank, it appears that I'm around 10kyu (give or take, depending on the system). Already I am seeing that I will sometimes lose to a 15kyu, and other times beat an 8kyu.

I suspect that, no matter your rank (at least in the kyus), a player a few stones weaker may very well be stronger than you in certain areas of the game and find ways to exploit that.
Author:  Solomon [ Sun Apr 25, 2010 11:59 am ]
Post subject:  Re: Ranking - Consistency and One-offs
I think the question you're asking is way too general for the very reason you've given.

But just for fun/the lulz, here's what I think for the number of games I'd probably win if I played against a legitimate ?d player on KGS in an even game:

7d - 5/50
6d - 15/50
5d - 20/50
4d - 25/50
3d - 30/50
2d - 35/50
1d - 45/50
Author:  Phelan [ Sun Apr 25, 2010 12:01 pm ]
Post subject:  Re: Ranking - Consistency and One-offs
I think most people expect to beat and be beaten by opponents of their level about 50%. As the difference in levels increases, that percentage also does.

For more precision than that, well, it really depends on the rating system.
Author:  kirkmc [ Sun Apr 25, 2010 12:22 pm ]
Post subject:  Re: Ranking - Consistency and One-offs
I think there are several issues here. First, as the OP says, sometimes he'll play like a 15k, and others like an 8k. Especially in the DDK range, ranks are pretty amorphous. I know that at my level (5k), I play people sometimes who are clearly two stones weaker than me, and others who are easily one stone stronger.

I was once told that the KGS rating system - and presumably all rating systems - assume that there's a 50% chance of your winning (or losing) against someone who is of the same rank. That with a one-stone difference, in an even game, there's a 25% chance. And so on. Given the wide range of ranks at some levels, this is never true. I can beat a friend who's 3k in even games sometimes, but I lose to 6ks as well occasionally.

And, as the OP says, certain areas of the game can make a big difference. Playing someone who has better L&D skills, even if they're technically weaker, can make you lose.
Author:  schultz [ Sun Apr 25, 2010 5:47 pm ]
Post subject:  Re: Ranking - Consistency and One-offs
kirkmc wrote:
And, as the OP says, certain areas of the game can make a big difference. Playing someone who has better L&D skills, even if they're technically weaker, can make you lose.

Don't know how many times this has happened to me :roll:. Hooray for good reading on a situation where I should know better. ;)

This brings up what I really like about Go. As long as your rank is decently established and you're within the same ranking system, handicapping works very well. I've seen this work quite often for me (and for others) where we can get a good game in, with about a 50-50 chance at who's going to win.

When you're in the DDK ranks, though, it does make it a bit harder to get the "stable" rank. Reminds me of one of the guys I used to play go with relatively frequently. One of the most inconsistent players ever. Definitely see him go from probably about 12k-20k from week to week. ;)
Author:  freegame [ Mon Apr 26, 2010 3:20 am ]
Post subject:  Re: Ranking - Consistency and One-offs
you can find info on this topic on senseis

http://senseis.xmp.net/?EGFWinningStatistics
http://senseis.xmp.net/?EGFRatingSystem
Author:  HermanHiddema [ Mon Apr 26, 2010 3:36 am ]
Post subject:  Re: Ranking - Consistency and One-offs
To make quick estimates, I use the formula: 1/(1+2^d), where d is the rank difference.

So if someone is 1 rank stronger, I expect to win 1/3, two ranks I expect to win about1 in 5, etc. In a list:
  • 1 rank stronger: 33%
  • 2 ranks stronger: 20%
  • 3 ranks stronger: 11%
  • 4 ranks stronger: 6%
  • 5 ranks stronger: 3%

Although really at 4 ranks stronger or more, I expect to have no chance, but terrible blunders do happen :)

Against weaker players, it is exactly opposite, so 67%, 80%, 89%, 94%, 97% respectively.
Author:  topazg [ Mon Apr 26, 2010 3:40 am ]
Post subject:  Re: Ranking - Consistency and One-offs
HermanHiddema wrote:
Although really at 4 ranks stronger or more, I expect to have no chance, but terrible blunders do happen :)


Of course, consistency tends to increase with strength, and as 4 stones stronger than you is professional strength, it is understandable you wouldn't favour your odds so much ;)
Author:  MagicMagor [ Wed Apr 28, 2010 2:43 am ]
Post subject:  Re: Ranking - Consistency and One-offs
I think the nice thing about this is, you can ask yourself what this tells you about your go, your strength and weaknesses.

Losing to much against player of a lower rank could mean you are bad at punishing mistakes or taking advantage of slightly better positions.
Winning against stronger opponents could mean you don't leave that much weaknesses in your positions which the stronger player could take advantage of.
Both together could mean you play overly defensive/fearfull and don't fight as much as you could. (Because in most cases in a fight the stronger player should have a slight advantage due too his better reading - but of course this depends alot on the position (but then weaker players tend to leave more holes in a position than a stronger player) and on the players themself, some may be bad at reading for their level, but compensate this with supiorer strategic thinking)

Just something to think about.
Author:  judicata [ Wed Apr 28, 2010 8:52 am ]
Post subject:  Re: Ranking - Consistency and One-offs
MagicMagor wrote:
I think the nice thing about this is, you can ask yourself what this tells you about your go, your strength and weaknesses.


That makes a lot of sense. Of course, we're speaking in generalities, but still...
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