[awm]

Designing a good rating system is a pretty complex problem even if we assume we are rating pairs rather than individuals.

If we rate "masterpoints per session" then this deters people from playing in club games. After all, even if you win a small club game you might get something on the order of 0.5 or 0.6 masterpoints. Top players average a lot more than this per session playing in regionals. So this would mean that if (say) Fred were to play in a club game his rating would go down even if he wins. Of course, the alternative of rating "masterpoints over masterpoints possible" favors people who routinely win in weak club fields (getting 0.5/0.5 possible masterpoints) over people who do well but don't necessarily win in top flight events (say obtaining 22/150 possible points in LM pairs).

Things are made even more difficult by the observation that beating down bad players is not exactly the same skill set as doing well in a strong field. There's a pair at my local club that wins almost every time they play (occasionally someone has a big game and drops them to second or third). This is because they know all the club regulars and how to exploit their weaknesses (who to overbid against, who to double, etc). Looking at their scores, they must average about 95% of the matchpoints against the weak pairs and less than 50% against the good pairs! In any case, there are other pairs at the club who routinely do respectably in regional or national events (and do well against this pair when at their table) who are probably "better" than these two, yet the club standings would indicate otherwise... The point being that there are pairs who can score in the mid-50s routinely in LM pairs who do only slightly better in the local club game, whereas there are other pairs who would be totally out of their depth in LM pairs but can score over 60 in the local club game routinely.

This is not true of chess, where any player who can beat grand masters will win routinely at his local chess club.

[jmc]

I agree that rating systems are very complex. They can also have some unintended consequences. i.e. there are chess players that play just enough to keep their ratings fresh, but not too much because they don't want to risk dropping below 2000 or 1900 or whatever. I'm sure the ACBL does not want to discourage people from playing in any way. BUT...

My current concern is that the ACBL announced a system was coming. The announcement made it sound forthwith. Then it disapeared. This is neither professional nor proper. ACBL members spend dues and entry fees to have a quality run organization. If it wasn't ready, they should have announced they were considering it, or entertaining proposals, or <gasp> not announced it at all.

jmc

[geller]

There are two functions of a rating system. One is to provide rankings of players (and from the point of view of the national federation) to incentivize players to play more. The flaws of the masterpoint system have been amply discussed in this thread and elsewhere, as have the difficulties in coming up with something demonstrably better. I don't have anything new to say about this.

But there is also a need for a rating system for flighting. This doesn't have to give am exact rating; just a rough and ready system is OK. The system we use in Japan is as follows. Each player has a "seeding point" (SP) total updated monthly. This number is computed from the player's masterpoints (MP) as follows

SP = 0.05 * min(career MP total, 3000) + 0.5 * (MP won in last 12 months)

The SP of a pair is the total of the two players, and the SP for a team is the sum of the four top players. Pairs or teams are flighted by SP totals. Different countries would want to tinker with the constants in the above formula based on the details of their MP system, but the above seems to provide a workable flighting system that almost all players are happy with.

[hotShot]

joshs, on Aug 22 2007, 05:11 PM, said:

Well I am not sure this gives a very good ranking:
Imagine 4 pairs playing, A B C D, all starting even:
Event 1:
A wins
B 2nd
C 3'rd
D 4'th

So the Ratings are now: +3, +1, -1, -3

Event 2:
Same result as event 1

Ratings stay the same: +3, +1, -1, -3

Event 3:
Again the Same

Ratings still at : +3, +1, -1, -3

Event 4:
B wins
A 2'nd
D 3'rd
C 4'th

Ratings are now: +2, +2, -2, -2

So even though A beat B 3/4 times and C beat D 3/4 times there ratings are the same.

The question is, how significant is 1 point?
If you think of a bigger tourney with 100 tables, the rankings will be between
+400 and - 400. I expect that values of 3500+ for world class player and 500 for beginners will be reached over time. I would consider less than 10 points as not very significant.

In your example A and B won 4/4 times over C and D.
A was 4-6 points better than C/D
B was 2-4 points better than C/D

A's ranking was between +3 and +2.
B's ranking was between +2 and +1.
C's ranking was between -1 and -2.
D's ranking was between -2 and -3.

This means that the ranking is quite stable, within this group.

Now assume that B came from some other club and has ranking up to +20. AC and D have a ranking of 0.
After your first event: the rankings will be:
+3, +19, 0, -2
After the 2nd event:
+4, +18, 0, -2
After the 3rd event:
+5, +17, 0, -2
After your 4th event:
+5, +17, -1, -1

So ever a longer period of time A and B will get to the same level, although A is not playing outside the club. And because B is loosing points to A in this club, B can regain points playing at the other club.

[barmar]

jmc, on Aug 22 2007, 09:08 PM, said:

My current concern is that the ACBL announced a system was coming. The announcement made it sound forthwith. Then it disapeared. This is neither professional nor proper. ACBL members spend dues and entry fees to have a quality run organization. If it wasn't ready, they should have announced they were considering it, or entertaining proposals, or <gasp> not announced it at all.

IIRC, all they announced was that they were starting to work on it, not that it was around the corner. Furthermore, they pretty clearly stated that the first pass would be targeted only at high-level events (which to me suggests that it might be an adaptation of the way they do seeding points for NABC+ events). In time they may expand it to all players.

[jmc]

I'll look for the article barmar but I think you are wrong. I think J. Baum wrote the article in Nov and implied the new system would begin in January. I think he also implied the method was ready and kinks just needed to be worked out. I'll try and find it to read it again.

To announce and wait nearly a year before saying whats up is still ridiculous IMHO.

jmc

[barmar]

I found the following in the ACBL CEO Report:

2.04 Develop ranking system based on current performance.
Management continues to search for a model that can meet the needs of our players, tournament organizers and TDs. This was scheduled for start up in 2007 with completion in 2008. We have received many comments and a few ideas from the membership. There is a great desire for this to take place. This is the largest challenge to complete for ACBL programmers, administrators and management.

[mike777]

barmar, on Aug 29 2007, 05:25 PM, said:

I found the following in the ACBL CEO Report:

2.04 Develop ranking system based on current performance.
Management continues to search for a model that can meet the needs of our players, tournament organizers and TDs. This was scheduled for start up in 2007 with completion in 2008. We have received many comments and a few ideas from the membership. There is a great desire for this to take place. This is the largest challenge to complete for ACBL programmers, administrators and management.

This is the ACBL's largest challenge for its programmers, admin and management?


Not online sect or reg tourney's?

I see in the same report a pilot program for online tourneys was supposed to be launched in July? I wonder how it went?

[jtfanclub]

mike777, on Aug 29 2007, 06:41 PM, said:

Not online  sect or reg tourney's?

Online sectional and regional tourneys would be suicide for the ACBL.

Think about it from the ACBL's point of view, and not yours, and it should be obvious. Move ACBL sectional and regional tourneys online, and the ACBL will literally cease to exist.

The problem is not technological. The problem is employment.

I think enough people at the ACBL understand this that it won't happen. We can have occasional club silver tourneys (eg. online club championships), but the ACBL is already running into the 'why should I pay $6 to go to a club when I can spend $1 to play at home', and over a very short period of time, that's going to really hurt the clubs. Since clubs are how most people get introduced to the ACBL, that's going to lose them their first level.

For sectionals and regionals, it'll be worse. Why spend lots of a plane ticket, hotel rooms, and then $8 or $10 a session when you can play for a couple of bucks at home?

And when the clubs and the smaller tourneys are gone, and the ACBL is reduced to a ratings system, the nationals, and some semi paid guys on web sites, somebody will come along with a better ratings system and payoffs, and snuff the ACBL out. Then we won't have the ACBL at all, just a USBF for international competitions.

Just a matter of time.

[mike777]

jtfanclub, on Aug 29 2007, 07:00 PM, said:

mike777, on Aug 29 2007, 06:41 PM, said:

Not online  sect or reg tourney's?

Online sectional and regional tourneys would be suicide for the ACBL.

Think about it from the ACBL's point of view, and not yours, and it should be obvious. Move ACBL sectional and regional tourneys online, and the ACBL will literally cease to exist.

The problem is not technological. The problem is employment.

Well this report says they have a pilot program for july 2007 for online sect and reg.

Anyone know the results?
I understand security is a huge issue.

[Foxx]

This whole thing scares the living ***** out of me.

Have any of you been adventurous (or foolhardy) enough to play bridge on pogo.com? Or Yahoo, which is similar and better known? That's what this setup would turn the whole world into. To make a long story short ---- for the everyday, common, casual bridge player the club and tournament scene would be a waking nightmare.

No, rating systems should be restricted to games (chess, checkers, scrabble, etc.) where one person controls his side's destiny.

[han]

The fact that ACBL uses masterpoints as the main factor to determine brackets bothers me, so I'm hopeful that a new rating system will improve things. It doesn't have to be perfect, "masterpoints won in the last 5 years" will already be more accurate.

The idea that "online bridge threatens ACBL so ACBL should fight it" seems wrong. ACBL should seek the best for its members, not its own interest. That is not necessarily the same.

[mike777]

Just got my acbl magazine, congrats to:
Han who finished 51st in the LM pairs
Phil who finished 5th in the LM-5000 pairs

I see Fred got his picture in the magazine this month. GrandLM