[dwar0123]

barmar, on 2012-May-07, 12:28, said:

I think rating systems like this have an inherent problem when you have subsets of players that generally play amongst themselves, but are mostly disconnected from other groups. With little overlap, you can't determine the relative strength of each group. And then you can't determine how the players from one group stack up against players in the other groups.

As an extreme example, suppose you have a group of experts who all play with each other, and a group of novices who do the same. Within the novice group, there may be a standout who regularly wins, so he would be given a high rating. Conversely, there must be an expert who isn't as good as his peers, so he would be given a low rating. But these two never play against each other, so the worst expert might be given a lower rating than the best novice, even though he's actually far better.

And for many players on BBO, this is a realistic situation. I don't think JEC enters many tourneys or plays with randoms in the MBC, he just plays his two JEC vs XXX team matches every day. He's a very good player, but he partners with some of the best, so the algorithm will assume that they're contributing more to the results.

I was thinking about this and also believe that part of the problem is that jec plays against a lot of very good opponents that don't otherwise play much on bbo and are thus very underrated.

I agree that isolated groups can not be compared to each other with any confidence. I do not agree that means they are a bad idea. If the system is any good, mixing the groups would fix the problem and if the players don't care to fix a what to them is a non problem then it is a non problem.

And obviously, that doesn't mean experts would have to play with novices, it just means experts would have to play with people who do play with people who do eventually through how ever many iterations play with novices.

[psantaana]

Hi:

I think that BBO could implement some ranking like the chess Elo rating system. It's based on how you perform against your oponents and whats the level diference between you and them. If your are a beter player, you are suposed to get a better result that if you are weaker than them. It's a really fair system.

Regards...

Pablo.

[hrothgar]

psantaana, on 2012-May-22, 16:25, said:

Hi:

I think that BBO could implement some ranking like the chess Elo rating system. It's based on how you perform against your oponents and whats the level diference between you and them. If your are a beter player, you are suposed to get a better result that if you are weaker than them. It's a really fair system.

Regards...

Pablo.

Be interesting to know how many times this suggestion has been made in the last 10 years

[RunemPard]

I do want to see an elo rating system set up...I would find it fun.

[Bbradley62]

dwar0123, on 2012-May-06, 22:21, said:

What about using robo tourny results as a way to rate people, not really exactly bridge, but certainty there is a direct relationship between the two and it would be pretty easy to call out that it is a robot tourny rating not a 'bridge playing' rating.

Robot tournaments are much closer to being "real bridge" than Automated Express Fun is!

[Bbradley62]

In addition to chess world, The United States Tennis Association also successfully uses such a system to rate its 330,000 league players.

[mycroft]

Now, that's a good case - how well does the Tennis ELO system rate pickup/unfamiliar vs practised doubles matches, or doubles matches with players who play doubles a lot vs a pair of singles players?

[Bbradley62]

USTA's system treats all matches the same, without regard to any of those variables you mentioned. Presumably, they reasonably even out over time. The ratings seem to pretty consistently be accurate.

[lycier]

Hello:

I think rating system is absolutely not to be employed. If you can not believe my opinion and employ such style ,I can bet that newly registering users will increase exponentially with many of anomalies, because it encourage Cheating with helps of each other,let many people keep a false pride ,even if merely for tiny scores,and nothing with others of social benifit .This design scheme is a very very bad if wanna to establish the integral manner.

[32519]

Naah! Much easier way to solve this. Currently we have:
1. Main Bridge Club
2. Relaxed Bridge Club

Just create a third one: Expert Bridge Club. The table host can activate "Permission required to join" for players. Anybody can initially "Request to play" by the table host. Give the guy a chance first time round. If it turns out the guy is a novice, boot him off the table and mark him as an enemy. When he tries to join a table on a later date it is now easy to "Reject."

[Quantumcat]

barmar, on 2012-May-07, 12:28, said:

I think rating systems like this have an inherent problem when you have subsets of players that generally play amongst themselves, but are mostly disconnected from other groups. With little overlap, you can't determine the relative strength of each group. And then you can't determine how the players from one group stack up against players in the other groups.

This is the same problem with Australia's rating system. Someone played in a small country town for a few years, and naturally beat all the little old ladies on a regular basis. But they would be quite pleased if they finished in the top quarter on a national event. For a while, they were rated in the top 20 players in Australia, ahead of multiple-national champions, and people who represented Australia overseas. Obviously the rating system doesn't work!