Tuesday, June 20, 2006

Can MahjongTime Rating System be Improved?

We have received inquires from members of our website regarding our ranking formula. The formula is based on Official International rules:

RatingNew= RatingOld+(Score+Difficulty-RatingOld)/41

Gamefactor = 40 on the gamefactor is static -- this is a number to average
out the luck factor of the game

Difficulty = average of all the participating players' ratings.

There are a few questions that we are getting from members:
1. Should we decrease the ratings for users that do not play for a while on the website?
2. Currently if at least 2 real players are on the table the rating is calculated. Should we change the way the rating is calculated in case when users leave the table?
What can be done to improve our rating system? Please post your opinions below.

14 comments:

Anonymous said...

hi, you know when you play 4 rounds of game. and people start leaving in the middle of it just because you are doing well. I think it's unfair that i dont' get my ratings coz i have no one on the table anymore. i think that the ratings should be place anyway. wether or not everyone left. IT'S unfair. and i think that should be changed. ASAP. thanks.

Anonymous said...

easy way to address comment 1, is to re-calc after each game rather than each round,solves his problem.

Make the rating system as clear to people on the site as ir is on the blog page,its not as clear how it works on the actual site.

oh,one other thing, let people know which season and flower is attached to each wind somewhere on the site,as far as I can see its not on there at all

Anonymous said...

To what I know...
Spring=East
Summer=South
Autumn=West
Winter=North

I don't have a clue about the flowers.

Rating: if people leave on any type of game, the last user should get their points. Any user can return if they are disconnected. If they leave then they "don't care". This should be explicit in the rules to avoid future complaints.

Rating should _never_ be negative. Sometimes we win a game and our rating is reduced which is not nice.

Anonymous said...

Hi there - here are the corresponding flowers & seasons with their winds:

East = spring, plum
South = summer, orchid
West = autumn, chrysanthemum
North = winter, bamboo

See you at the tables,
Nikkos888

a3geffen said...

To gain game credits you have to score over 50% winning. So even good players are losing their account. They start again with 0.1.
To increase my rating I cannot afford to play with 2 people with less than 10 rating. To increase my own rating I have to score very heavy.
All in all the average rating will decrease, especially for CO-players.
I would like to see a winnning of 3 game credits instead of 2 (before it was 4) to let people build up their rating.
Furthermore I suggest that you let the score count double in determining the new rating.

a3geffen said...

To gain game credits you have to score over 50% winning. So even good players are losing their account. They start again with 0.1.
To increase my rating I cannot afford to play with 2 people with less than 10 rating. To increase my own rating I have to score very heavy.
All in all the average rating will decrease, especially for CO-players.
I would like to see a winnning of 3 game credits instead of 2 (before it was 4) to let people build up their rating.
Furthermore I suggest that you let the score count double in determining the new rating.

Anonymous said...

I was just on a table of 1 rnd of CO. 4 people took a seat. we started the game and 1 person never played but didn't leave the game. that lasted for over 1 game. i asked for online help but never heard from John(PS).

if we leave we lose credits and hurt our rating. i suggest that someone who misses 10 discards be automatically ejected from the game. The computer takes over but that is better than waiting 15 or more seconds on every move. And the rating for the missing person should be affected by a couple of points.

it is very frustrating to be trapped for a whole round. Don't know why i never heard back from the Live Help.

Thanks for letting me vent.

Eric De Cleric said...

Serious penaltys should be built into the rating system to try and cut out the rapidly growing problem of people dropping out at the start of a game because they dont have a good hand. This leaves the other three in worse situation than when jerrybot is playing.
Also please think carefully about introducing a multi game play option as sugested. This will hugly increase the problem mentioned above. People will join several games and drop out of the ones with bad hands. I see disaster there. Perhaps it would work if a player lost all his games if he dropped out on any one of them

Anonymous said...

In the explaination the word Gamefactor is mentioned, but isn't used in the formula. It is a static number of 40 (to rule out luck), but i can't fit it in the formula. So please can be the correct formula be posted.

And if you want my opinion about the current formula, i think the rating chance should be based on number of rounds played the more hands you play in one game the more you rule out the luck factor. Everybody can have a bad starting hand, but 4 in a row is very slim. The rating change is the same for a Quick game as for a complete game consisting of 4 rounds. This is not realistic. Everybody can win one wall (with Quick Mahjong), but coming out ahead after 4 rounds is another story. If still want to use the current formula i would recommend to extend the formula to:
RatingNew = RatingOld + ((Score + Difficulty - RatingOld) / 41) * NumberOfHands / 4

Making a 1 round game a normal rating chance, a Quick Mahjong only 25% but a full game 400% chance. The more you play the more you rule out luck and the more accurate your endposition is.

Just my 2 cents,

GRDavies

MahjongTime said...

We greatly appreciate all the comments and feedback. Based on your feedback we have done the following changes to the game:
1. Rating will decrease with a rate of 1% per month if a player has not played for a month
2. Added numbers to flowers seasons

As some players have mentioned above, many tables get abandoned by players during the game and it looks like it is unfair for the players that have good scores if the game becomes not rated (any game becomes unrated if there is only one player at a table). So it makes sense to calculate the rating after each hand.

If we go the way that GRDavies proposes: the rating needs to be calculated only after a game is finished and give only ¼ of rating points for “quick mahjong”.
The current formula is based on number of deals (hands) you play. Then more play then more you rule out of luck factor. The formula should average the rating in about 40 deals and it doesn’t matter if it was a round or 4 rounds game.

In some cases the rating could be negative: If you play against low rated (players with negative rating) then even if you win your rating may drop. Normally it happens when you win with a low score. It looks like it makes sense to not punish high rated players play against new players that just start and have a low rating

The following features are scheduled for development:
1. Calculate rating after each deal(hand)
2. In case of win, make the rating never go down.
3. Different rating for each style of mahjong.

Atticus said...

From above, written in 2006:

The following features are scheduled for development:
1. Calculate rating after each deal(hand)
2. In case of win, make the rating never go down.
3. Different rating for each style of mahjong.


I learned today that only #2 remains unfinished; in my opinion it's the most important one of the three.

I support the policy of getting more rating points when playing against higher rankings (they do the same thing in Bridge Tournaments).

However, no winning hand should ever lead to deducting rating points. It is true that this could only happen in rare cases, but even then, a win should always increase a player's rating, no matter how small that increase might be (when playing against rank-beginners).

Best to all,

Atticus

MahjongTime said...

The “Make the rating never go down in case of win” development feature has been in place since 2006. Under any circumstances, a player’s rating will never go down if they win a game.
A player may win hands in a game, and may have a score greater than zero, but if they do not have the most points in the game and are not winners of the entire game, their rating may go down. However, if a player has the most points in the game and wins the game, their rating will Never decrease.

MahjongTime said...

Mahjong Time has changed the way you get rated for Quick Mahjong games that better represents an individual player's prowess. This change was implemented some time ago, we simply want our players to be aware of the new calculations.



Here is our new formula for Quick Mahjong Games:



OldRating +( (Score*4 + Difficulty –OldRating)/41 ) /4





For game where there are multiple rounds in the game, we have a different rating calculation:



OldRating +( (Score * (4/Rounds) + (Difficulty –OldRating) / (4*Rounds) ) /41) / (4/Rounds)



We calculate the "difficulty" by figuring out the average of all the participating players' ratings. For the games with more than 1 deal, your rating is calculated for each deal separately after the deal finishes.



The calculations might look complicated, but they are easy to figure out and give a true and fair representation of your rating.



Any comments or questions on our new system?? We always appreciate and take into consideration player feedback.

Anonymous said...

2 questions :
1) What is the exact formula of the rating caculation after each round ? Obviously it's not the one you give in answer in your blog (I checked it on a game, it does not work at all).
2) You were talking about having your randomnes generator audited by an independant organism. Where could we learn about this audit ?
Thank you for answering me.