How in the heck do the KC ratings work?The Kings Cribbage rating system is based off a subset of the proven standard chess ratings system.
I will try to explain the best I can here, but for further technical details, click here.
Standard Game RatingsAn average player in our KC community is rated 1500 (Commoner). Everyone starts off at a provisional 1500 rating. (We will discuss provisional further down)
The average amount of ratings points gained or lost in a match is 21.
ie If two players have the same rating, one will win 21 ratings points, the other will lose 21 ratings points.
The bigger the difference between ratings, the more the underdog would go up if they won,
and the more the favored player would go down if they lost. Here is the formula:
Rnew = Rold + (S x 21) + (Ropponent - Rold) / 25
Rnew = the new rating for either player
Rold = his or her old (pre-game) rating
S = his or her SCORE for the game;
This is +1 for a WIN,
0 for a DRAW,
-1 for a LOSS
Ropponent = the pre-game rating of the opponentSo let's say a 1700 (Knight) player plays a 1500 (Commoner) player.
Let's say the knight wins. Using the formula above:
Knight's rating change = 1700 + 21 + -8 = 1713
Commoner's rating change = 1500 - 21 + 8 = 1487
Since the knight was expected to win, they will only go up 13 ratings points, and the Commoner will only drop 13 ratings points.
However if the commoner upsets the Knight, using the same formula, the commoner will go up 29 ratings points,
and the knight will drop 29 ratings points.
The maximum number of points you can gain or lose in a standard non skunked (more on skunks later) game is 41.
ie if Mrs. Peasant (1250) very unexpectedly defeats Mr. Lord (1850), Mrs. Peasant will go up 41 to 1291 and Mr. Lord will drop to 1809.
The minimum number of points you can gain or lose is 2. ie Mr. Lord beats Mrs. Peasant. Mr. Lord will go up 2 points,
and Mrs. Peasant will drop 2 points since this was a very expected outcome.
Ratings for Provisional PlayersRules are a bit different when provisional players are involved. A provisional player is someone who has played less than
10 games. The system will try to figure out where they belong in the ratings based on those first 10 games.
Provisional players ratings will bounce up and down a lot when they play rated players as the system tries to figure out
where they fit in. Conversely, a rated players rating will not change much when playing a provisional player since
we don't really know how good that provisional player is yet.
When two provisional players play each other, the same formula as the Standard game applies.
When a rated player plays a provisional player, here are the formulas used. Formula 1 is the adjustment to the rated
player, and formula 2 is the adjustment to the provisional player.
Formula 1: Rnew = Rold + (S x 6) + (Ropponent - Rold) / 100
Formula 2: Rnew = (4 / 5) x Rold + (1 / 5) x Ropponent + (S x 80)
Group RatingsRatings are again different for group ratings. In fact there is a whole seperate category for group ratings because
group games are so different from head to head games. Group ratings are used for 3 and 4 player games.
Ratings points go up and down based on which place you finish (1st-4th), the overall skill level of your opponents,
and the skill level of the opponent you directly follow.
Example: Let's talk about a 3 player game with two knights and one peasant. The knight who is following the peasant
will have a better chance ton win statistically since the peasant will be setting up the knight for easy moves
more often than the knight would.
If the knight following the peasant wins, their rating wouldn't go up as much as if the knight following the knight would
have won. If the peasant beat both the knights, their rating would go up significantly higher in the group ratings.
SkunksDo you see the little skunk popping up in your game sometimes? This has significance on the ratings adjustments.
If a player wins by 75 points or more, their ratings points gained will be boosted by 1.5 times. So if they normally
would have gained 20 points with a win, now they will gain 30!
Even more crazy, a DOUBLE skunk is a win by 150 points or more! In this case your ratings points will be adjusted 2 times.
So now you would have gained 40 ratings points with a win instead of just 20 with a standard win.
So now if an 1100(Servant) player double skunks a 2100(Queen) player, they would go up 41*2 = 82 points!
The Queen would also drop 82 points. So if you ever want to go up a lot in the ratings, go find a 2000+ rated player,
and go double skunk them! (good luck)
SummaryBasically overall, the better opponent you beat, the more your rating will go up. The worse opponent you lose to,
the more your rating will go down! Wasn't that easier than reading through all that! :)