Question about ratings on redhotpawn.com

skims

Help

27 Jun 05

skims

Joined: 23 Jun 05
Moves: 3744

27 Jun 05

What happens if a provisionally ranked 1200 player draws with another provisionally ranked 1200 player in a rated game?

Will either rating change after the game?

Wildfire

Force of Nature

The Bathroom

Joined: 12 May 05
Moves: 31388

27 Jun 05

Originally posted by skims
What happens if a provisionally ranked 1200 player draws with another provisionally ranked 1200 player in a rated game?

Will either rating change after the game?

I have no clue. Why don't you try it yourself.

Bowmann

Non-Subscriber

RHP IQ

Joined: 17 Mar 05
Moves: 1345

03 Jul 05

Now we know the answer.

Wildfire

Force of Nature

The Bathroom

Joined: 12 May 05
Moves: 31388

03 Jul 05

Originally posted by Bowmann
Now we know the answer.

Go play in someone else's sandbox.

Bowmann

Non-Subscriber

RHP IQ

Joined: 17 Mar 05
Moves: 1345

03 Jul 05

Originally posted by Wildfire
Go play in someone else's sandbox.

That reminds me, when's Katty due back?

Nicolaas

Joined: 07 Jan 05
Moves: 20117

04 Jul 05

meeuw!

Daemon Sin

I'm A Mighty Pirate™

PaTROLLING the forum

Joined: 01 Dec 04
Moves: 36332

04 Jul 05

Originally posted by Bowmann
That reminds me, when's Katty due back?

Why, you fed up chasing cars and p*ss*ng on trees already so you need your favourite leg to hump?

Invader

Joined: 18 Jun 05
Moves: 6610

06 Jul 05

If you have less than 5 games, no. Otherwise I have attepted the math:

K=32

Old Rating=1200

Score = .5

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/200)+1)
= 1 / (10^((1200-1200/200)+1)
= 1 / (10^1)
= 1 / 10
= .1

New Rating = Old Rating + K * (Score - Win Expectancy)
= 1200 + 32 * (.5 - .1)
= 1200 + 32 * .4
= 1200 + 12.8
= 1213

XanthosNZ

Cancerous Bus Crash

p^2.sin(phi)

Joined: 06 Sep 04
Moves: 25076

06 Jul 05

Originally posted by Invader
If you have less than 5 games, no. Otherwise I have attepted the math:

K=32

Old Rating=1200

Score = .5

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/200)+1)
= 1 / (10^((1200-1200/200)+1)
= 1 / (10^1)
= 1 / 10
= .1

New Rating = Old Rating + K * (Score - Win Expectancy)
...[text shortened]... 0 + 32 * (.5 - .1)
= 1200 + 32 * .4
= 1200 + 12.8
= 1213

The win expectancy formula is used when you have played more than 20 games (your rating isn't provisional anymore).

Until you complete 20 games (and you've completed more than 5) your rating is the average of all your game values.
The game value is your opponent's rating + 400 if you win , -400 if you lose. It's equal to your opponent's rating if you draw.
If your opponent is provisional the 400s are 200s.

Therefore if two p1200's play each other and draw no change is made to their ratings.

Florrat

Joined: 24 May 05
Moves: 1958

06 Jul 05

Originally posted by Invader
If you have less than 5 games, no. Otherwise I have attepted the math:

K=32

Old Rating=1200

Score = .5

Win Expectancy = 1 / (10^((OpponentRating-YourRating)/200)+1)
= 1 / (10^((1200-1200/200)+1)
= 1 / (10^1)
= 1 / 10
= .1

New Rating = Old Rating + K * (Score - Win Expectancy)
...[text shortened]... 0 + 32 * (.5 - .1)
= 1200 + 32 * .4
= 1200 + 12.8
= 1213

what's 'K'?
is it always 32?

XanthosNZ

Cancerous Bus Crash

p^2.sin(phi)

Joined: 06 Sep 04
Moves: 25076

06 Jul 05

Originally posted by Florrat
what's 'K'?
is it always 32?

Read the FAQ, it has a detailed breakdown for the rating calculation:

"K is a constant (32 for 0-2099, 24 for 2100-2399, 16 for 2400 and above)"

The numbers are your rating.