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Change Masterpoint Calculation Formula

#1 User is online   riverwalk3 

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Posted 2022-May-25, 20:34

It seems like the masterpoint formula rewards events with more players. A fair formula would have total masterpoints awarded increase linearly with the number of players, but it seems to increase quadratically. The current formula means that if you get each place with equal probability, you gain more masterpoints per tournament on average in larger tournaments. In a fair formula, if you score each place with equal probability, you get the same amount of masterpoints per tournament no matter the tournament size.

This means that you can spend a lot of money on a tournament, but if only a few players show up, you won't get much bang for your buck no matter how well you do. On the other hand, the daylong tournaments give insane amount of points and are relatively cheap due to the number of players that play them.
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#2 User is offline   Douglas43 

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Posted 2022-May-25, 23:11

View Postriverwalk3, on 2022-May-25, 20:34, said:

It seems like the masterpoint formula rewards events with more players. A fair formula would have total masterpoints awarded increase linearly with the number of players, but it seems to increase quadratically. The current formula means that if you get each place with equal probability, you gain more masterpoints per tournament on average in larger tournaments. In a fair formula, if you score each place with equal probability, you get the same amount of masterpoints per tournament no matter the tournament size.

This means that you can spend a lot of money on a tournament, but if only a few players show up, you won't get much bang for your buck no matter how well you do. On the other hand, the daylong tournaments give insane amount of points and are relatively cheap due to the number of players that play them.


If it's BBO points I can't comment because I've not seen the formula. Would you mind posting it please? The EBU does the opposite to what you describe, and masterpoint awards grow more slowly as the numbers of entries get higher.
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#3 User is online   riverwalk3 

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Posted Yesterday, 00:33

View PostDouglas43, on 2022-May-25, 23:11, said:

If it's BBO points I can't comment because I've not seen the formula. Would you mind posting it please? The EBU does the opposite to what you describe, and masterpoint awards grow more slowly as the numbers of entries get higher.

I don't know the exact formula for BBO points, but:

In BBO points the reward for Daylong tournaments is really high due to the number of participants. The winner gets nearly 30 points for example, and the points seems to decrease linearly rather than exponentially. The average number of points rewarded per participant was 1.39 in the last Zenith tournament that I played from a spreadsheet calculation. My best performance on a Zenith daylong tournament was about 30th place, which got me over 14 BBO points. On the other hand, a Robot Rebate tournament might only have 3 participants, in which the winner only gets 0.18 masterpoints (or about 0.06 average). Both cost $1 and the Zenith has a higher percentage of cash-out (generally 1/3 of the players get 55% from my experience, so the Rebate tournament has a payout ratio of 0.5 while the Zenith tournament has a payout ratio of 0.8).

ACBL seems to segment, so your score is only compared against 15 or so other players. Usually the winner doesn't get more than a reasonable number of masterpoints (such as 1.5).
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#4 User is online   smerriman 

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Posted Yesterday, 00:46

It's the same as the ACBL formula: https://blog.bridgeb...bo-points-work/
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#5 User is online   riverwalk3 

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Posted Yesterday, 01:25

View Postsmerriman, on 2022-May-26, 00:46, said:

It's the same as the ACBL formula: https://blog.bridgeb...bo-points-work/

For daylong tournaments the top reward does not cap out at 15 tables. It seems indefinite.
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#6 User is offline   barmar 

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Posted Yesterday, 08:55

View Postriverwalk3, on 2022-May-26, 01:25, said:

For daylong tournaments the top reward does not cap out at 15 tables. It seems indefinite.

That's correct. We felt that defeating thousands of other players should be rewarded far more than beating just a few dozen players.

Here's the formula for BBO daylongs with 12-17 tables.

The award for 1st place is 0.06/table for the first 15 tables + 0.03/table for the next 45 tables + 0.015/table for all the rest. Since most daylongs have far more than 60 tables, it's basically linear. I think the formula for the fist 15 tables was chosen to be the same as the section awards in traditional tourneys, the others just came out of someone's a** were arbitrarily chosen adjustments.

Points are awarded to the top 40% of the field, and the last award is 0.01.

The points in between are calculated using exponential decay.

If there are 18 or more boards, the points for 1st place are increased by 25%. If there are fewer than 12 boards, the top award from the above calculation is multiplied by boards/12. The rest of the calculation remains the same.

ACBL daylongs and the NABC Robot Individual are completely different.

#7 User is online   fhacker 

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Posted Today, 17:12

Riverwalk takes issue with the fact that large events pay many more masterpoints than small ones and that this is unfair financially to people unfortunate enough to find themselves in a small event. The ACBL awards points based on the number of tables in an event and the type of competition (club, sectional, regional national, etc.) The more difficult an event is to win, the more points you get for winning it. Seems fair to me. I believe master points per dollar of player entry fee is an illogical substitute for the traditional parameters.

I do not understand Riverwalks' description of what is fair. I do not understand why he thinks masterpoints increase quadratically instead of linearly. I do not understand what he means by scoring each place with equal probability. He says that the number of masterpoints should be the same regardless of tournament size. I think one consequence of that would be that winners of small tournaments may get more points than winners of large tournaments. That seems a logical consequence of spreading the same number of points among fewer players.

Now for the masterpoint formulas. I usually play in 12 or 18 board games with a single section or a large number of sections. The ACBL requires at least 18 boards to award masterpoints at the full club level. Below that the awards are 60% of club level.

For flight A the 18 board single section formula is .1 times the number of tables up to a maximum of 1.50. For 12 board the formula is .06 up to a max of .9. For multiple section events, there are also overall awards. For 18 board events, these are .1 times the number of tables up to a maximum of 4.00. For 12 boards it's .06 per table up to a maximium of 2.4

This means that the overall award for a 30 table event is 3.00, for a 40 table event, it's 4.00. For 100 tables, it's still 4.00. I'm not sure of the awards for flights B and C. Flight B awards are usually 80% of flight A awards based on the number of tables in flight B and below. Flight B and C partipants are eligible for flight A awards.

None of this seems to be quadratic. It is linear until it levels off.
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#8 User is online   riverwalk3 

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Posted Today, 21:52

View Postfhacker, on 2022-May-27, 17:12, said:

Riverwalk takes issue with the fact that large events pay many more masterpoints than small ones and that this is unfair financially to people unfortunate enough to find themselves in a small event. The ACBL awards points based on the number of tables in an event and the type of competition (club, sectional, regional national, etc.) The more difficult an event is to win, the more points you get for winning it. Seems fair to me. I believe master points per dollar of player entry fee is an illogical substitute for the traditional parameters.

I do not understand Riverwalks' description of what is fair. I do not understand why he thinks masterpoints increase quadratically instead of linearly. I do not understand what he means by scoring each place with equal probability. He says that the number of masterpoints should be the same regardless of tournament size. I think one consequence of that would be that winners of small tournaments may get more points than winners of large tournaments. That seems a logical consequence of spreading the same number of points among fewer players.

Now for the masterpoint formulas. I usually play in 12 or 18 board games with a single section or a large number of sections. The ACBL requires at least 18 boards to award masterpoints at the full club level. Below that the awards are 60% of club level.

For flight A the 18 board single section formula is .1 times the number of tables up to a maximum of 1.50. For 12 board the formula is .06 up to a max of .9. For multiple section events, there are also overall awards. For 18 board events, these are .1 times the number of tables up to a maximum of 4.00. For 12 boards it's .06 per table up to a maximium of 2.4

This means that the overall award for a 30 table event is 3.00, for a 40 table event, it's 4.00. For 100 tables, it's still 4.00. I'm not sure of the awards for flights B and C. Flight B awards are usually 80% of flight A awards based on the number of tables in flight B and below. Flight B and C partipants are eligible for flight A awards.

None of this seems to be quadratic. It is linear until it levels off.

The point is that the total number of masterpoints awarded should scale linearly in the number of players (so the average number of masterpoints awarded per player is the same no matter the event size).

I'm getting a vast majority of my masterpoints from daylongs with the current formula. Scoring 30th place in the Zenith daylong gets you 14 masterpoints, far more than you can in way smaller tournaments even if you get first.
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