Chess and Elo system ?

Question

If a 1800 Elo player plays against a 2000 Elo player

-How many points does he win in case of win ?

-How many points does he win in case of draw ?

-How many points does he lose in case of loss ?

In brief, how did you make this calculation ?

Answer 1

Player A:1800

Player B: 2000

If A Beats B, A gains 18 points becoming 1818

If B Beats A, A loses 6 points becoming 1794

If A and B Draw, A gains 6 points becoming 1806

With a 200 point difference the Win expectancies are

A-0.24

B-0.76

W(e) for A=1/(1+(10^((1800-2000)/-400)))

W(e) for B=1/(1+(10^((2000-1800)/-400)))

A's new Rating=1800+(K*(S-W(e)))

K=24 (usually but not always)

S=(Win=1, Loss=0, Draw=0.5)

Answer 2

Brief?  Ha,Ha, Ha,

http://en.wikipedia.org/wiki/ELO_rating_...

Answer 3

A rough estimate is this:

In a given game, a maximum of 32 points can change hands.  This is weighted by the rating difference between the two players.  The maximum rating difference a player can be is 800 points difference, after that it is the same result.

Here is what I mean by this:  If two 1500 players play each other, and draw, they stay even as the points are divided between them evenly.  If there is a say 400 point difference between them a 1900 vs a 1500, and they draw, the 1900 would actually lose points and the 1500 gain them.  If the 1500 wins he will gain much more points than the 1900 if he wins.

Here is a site that calculates these in a java applet.

Unfortunately the formula is pretty complicated to have a general rule.

http://www.uschess.org/ratings/calculato...

Answer 4

what is the elo system.  I'd be curious to learn about it, can you expand your question