Average Plus and Average Minus

[jallerton]

Suppose that you are using the European VP scale of:

 

15-15

16-14

17-13

18-12

19-11

20-10

21-9

22-8

23-7

24-6

25-5

25-4

25-3

25-2

25-1

25-0

 

For a match which cannot be played, a TD wishes to assign average plus to Team A, average minus to Team B.

 

How many VPs should each team be given?

[shyams]

With this scale, if you had an odd number of teams, the Bye team usually gets 18 VPs. I am not sure if this is a universal practice, but I recall seeing it on atleast two separate occasions when I participated (not in UK).

 

Would it be fair to therefore assume 18 is Ave+ and 12 is Ave-?

[Cascade]

A+ is 3 IMPs.

 

In the absence of a special regulation I do not see why the match should not be scored as 3*n to 0 where n is the number of boards and converted to VPs using the appropriate scale.

[jdonn]

A+ is 3 IMPs.

 

In the absence of a special regulation I do not see why the match should not be scored as 3*n to 0 where n is the number of boards and converted to VPs using the appropriate scale.

I agree.

[campboy]

But there should be a special regulation in place, as the above approach is likely to give 25-0.

[jdonn]

But there should be a special regulation in place, as the above approach is likely to give 25-0.

From what I can see that's only true in a match of 34 or more boards. In an 8 board round it would be 23-7. In 16 boards it's 25-4, which does seem a little harsh but not outrageous IMO.

 

Maybe there should just be a regulation that dictates 25-5 for any length match.

[Cascade]

Perhaps the real problem is that for a one board adjustment +3 IMPs for Average plus is too generous.

 

I am not so sure that a special regulation should be required. If +x IMPs is reasonable for one board why should it not be reasonable for n boards.

 

Perhaps +1 IMP is a more reasonable average plus but that is not they way the laws are written.

 

+1 IMP is a pretty good average score and in my mind is not too dissimilar to 60% at matchpoint scoring (but, disclaimer, without thinking too carefully about the appropriate precise numbers).

[pran]

According to Norwegian regulations a team that fails to show up at a scheduled match receives 0 VP unless they can show "Force Majeure", in which case they receive 12 VP.

 

Their opponents (and also Bye teams in case of sit-outs) receive 18 VP.

 

I cannot imagine any other situation where a question of A+ or A- in VP can be relevant?

 

Both scores (12 and 18 VP) are subject to the usual adjustments for teams that score an average of less than 12 VP or more than 18 VP respectively over the matches they actually have played at the end of the tournament.

[jallerton]

Consider the example of a Swiss Teams or a round robin.

 

1. Suppose the teams sit incorrectly, such that an entire stanza or match is made void. How many VPs do you give to a side at fault for sitting in the wrong place?

 

2. Now suppose that the TD is responsible for the incorrect seating of the teams and that the players are in no way at fault.

 

In both cases, there is insufficient time to replay the match with substitute boards.

[pran]

Consider the example of a Swiss Teams or a round robin.

 

1.  Suppose the teams sit incorrectly, such that an entire stanza or match is made void.  How many VPs do you give to a side at fault for sitting in the wrong place?.

By regulation we award split scores: Each team is penalized 1 IMP for each board that cannot be scored. (Both teams must neccessarily be at fault for sitting incorrectly!)

 

Say that one complete round (16 boards) cannot be scored and that the other round ends with a tie (in IMPs). Each team then loses the match with 16 IMPs giving each a 13 - 17 VP loss.

 

2.  Now suppose that the TD is responsible for the incorrect seating of the teams and that the players are in no way at fault.

 

In both cases, there is insufficient time to replay the match with substitute boards.

The teams are responsible for their own seatings, it must be a very strange arrangement if the Director can be held responsible for teams seated incorrectly.

 

However, if that should ever happen to be the case I suppose we would award 18 VP

[bluejak]

The original question is a strange one. We do not award Ave+ or Ave- in VPs: read Law 12C2.

 

Any method that gives a team 25 VPs for not playing a match is outrageous.

 

12.20 Law 12: Redress for damage [Ton]

Average plus

An artificial adjusted score on a board in a Pairs event should be awarded only if a pair at the start of a session was scheduled to play that board, but for some reason could not obtain a normal result. A bye in a session should not result in an average-plus score; the pairs concerned play one or more boards fewer. Our advice is to restrict by regulation the number of boards on which an average plus score is given, for example, to two boards in a session. If there are more boards without a result obtained by normal play those boards are not scored.

This principle may not be accepted for three or four boards, but you cannot start giving 3 imps a board over a full match. So a regulation is reasonable. 18 VPs is used in many places.

 

The EBU does not worry too much about the 25-0 scale since they rarely use it, but have a general regulation of 1.5 imps a board. That is probably too generous, and leads to a win of between 19 and 23 VPs: that is too many.

[jdonn]

I think whatever guideline is used should indeed be very generous to any team not at fault. They lost their chance to win by more and that is not fair to them at all. Giving them 18 victory points is almost nothing when their starting point is 15, I find that much more outrageous (in the opposite direction) than giving them 25.

 

Btw why does that law say "Our advice"? Is it a law, or advice, or something else?

[mjj29]

Btw why does that law say "Our advice"? Is it a law, or advice, or something else?

The first part of the white book is comments / minutes / advice on particular laws. Their advice about Law 12 is ....

[Finch]

The teams are responsible for their own seatings, it must be a very strange arrangement if the Director can be held responsible for teams seated incorrectly.

What a strange comment. It's quite common for the TD to give instructions. In EBU events with multiple head-to-head matches such as the Crockfords final or the Premier League each table has a card telling you which team is sitting which way. The tables may be in separate rooms, so you aren't going to look across and see how your team-mates are sitting. A league in which I play always has a large piece of paper on each table saying e.g. "HINDEN NS AT THIS TABLE". It's possible for these to be wrong (although I've not yet seen it happen).

 

In the Semi & Final of the Spring 4s the matches are played in different rooms and the TD tells you which way you are sitting in each room.

[jallerton]

The original question is a strange one.  We do not award Ave+ or Ave- in VPs: read Law 12C2.

Sorry if I used the wrong terminology. How many VPs do you assign to a team when none of their match can be played and they are in no way at fault?

 

The EBU does not worry too much about the 25-0 scale since they rarely use it, but have a general regulation of 1.5 imps a board.  That is probably too generous, and leads to a win of between 19 and 23 VPs: that is too many.

 

The EBU uses the 25-0 scale for the Premier League and the final of Crockford's, which are two of England's most prestigious events. It is quite common for players to turn up late for bridge events, and when motorways are shut and railway lines become blocked it is not unknown for a journey delay to be more than the scheduled length of the first match.

 

There have also been a couple of occasions in the European Championships where one particular country's team has not arrived at the venue until the second match.

[pran]

The teams are responsible for their own seatings, it must be a very strange arrangement if the Director can be held responsible for teams seated incorrectly.

What a strange comment. It's quite common for the TD to give instructions. In EBU events with multiple head-to-head matches such as the Crockfords final or the Premier League each table has a card telling you which team is sitting which way. The tables may be in separate rooms, so you aren't going to look across and see how your team-mates are sitting. A league in which I play always has a large piece of paper on each table saying e.g. "HINDEN NS AT THIS TABLE". It's possible for these to be wrong (although I've not yet seen it happen).

 

In the Semi & Final of the Spring 4s the matches are played in different rooms and the TD tells you which way you are sitting in each room.

The seating information given to the teams include:

 

For each match which team is "home team" and which is "visiting team".

Which room is "open" and which room is "closed".

The reminder that "home team" sits North-South in the "open" room and East-West in the "closed" room.

 

The rest is left to the players.

 

(Our regulations suggest that the Director, unless he is busy with other tasks should verify the seatings at the beginning of each match, but clearly state that he is in no way responsible for undiscovered seating errors.)

[bluejak]

Very good, Sven. But the fact that you have particular teams events run in a particular way does not mean that the question is a silly one, for two reasons.

 

First, not every event throughout the world is run per Norwegian regulations.

 

Second, everyone makes mistakes, even Norwegian TDs. It may be incredibly rare, but I bet you cannot say that there has never been a seating problem ever in any Norwegian event that was the fault of the TD.

[pran]

Very good, Sven.  But the fact that you have particular teams events run in a particular way does not mean that the question is a silly one, for two reasons.

 

First, not every event throughout the world is run per Norwegian regulations.

 

Second, everyone makes mistakes, even Norwegian TDs.  It may be incredibly rare, but I bet you cannot say that there has never been a seating problem ever in any Norwegian event that was the fault of the TD.

I don't think that we have "particular teams events" run in any "particular way" in Norway and I have not said that the question is "silly".

 

But a fact is that the vast majority of teams matches in Norway are run without any Director present: Two teams meet for a knock-out match, they know perfectly well who is "home" and who is "visiting" (they have been told so by the NBO in advance) and they have no problem seating themselves at their own responsibilities.

 

When teams come to multiple teams events they are similarly told who is "home" and who is "visiting" and are already used to seat themselves at their own resposibility. The only information they really need from the Director is which room is now "open" and which is "closed".

 

It sure happens that teams seat themselves wrong, but I have yet to experience any case where this is the fault of the director.

 

I am fully aware that events outside Norway need not bother about Norwegian routines or regulations, but frankly: I don't see the problem, whether in Norway or anywhere else!

[bluejak]

I think whatever guideline is used should indeed be very generous to any team not at fault. They lost their chance to win by more and that is not fair to them at all. Giving them 18 victory points is almost nothing when their starting point is 15, I find that much more outrageous (in the opposite direction) than giving them 25.

Well, I do not. In the same way that Ave+ on a board is not 100%, I think it is very unfair to give a team a 100% score when they have not played.

 

I wonder how keen teams would be to play in difficult circumstances not caused by themselves if they get 100% for not playing? Splitting headaches would become routine. :)

 

Btw why does that law say "Our advice"? Is it a law, or advice, or something else?

Sorry: I thought it was clear. Silly me. Entries in the EBU White book that are labelled [Ton] are from a document produced by Ton Kooijman. While he is Chairman of the WBFLC and thus knowledgeable, the document is not an official WBFLC one, so it is Ton's advice. Why he says "our" rather than "my" I am not sure.

 

In the Semi & Final of the Spring 4s the matches are played in different rooms and the TD tells you which way you are sitting in each room.

And anyone who gets that wrong gets shot, in view of who the TD is. :P

 

The original question is a strange one.  We do not award Ave+ or Ave- in VPs: read Law 12C2.

Sorry if I used the wrong terminology. How many VPs do you assign to a team when none of their match can be played and they are in no way at fault?

Now the question becomes simple. That is a matter for regulation, and any organisation that does not have such a regulation is at fault.

 

The EBU does not worry too much about the 25-0 scale since they rarely use it, but have a general regulation of 1.5 imps a board.  That is probably too generous, and leads to a win of between 19 and 23 VPs: that is too many.

The EBU uses the 25-0 scale for the Premier League and the final of Crockford's, which are two of England's most prestigious events. It is quite common for players to turn up late for bridge events, and when motorways are shut and railway lines become blocked it is not unknown for a journey delay to be more than the scheduled length of the first match.

The fact that they are prestigious is irrelevant: the point is that the scale is used rarely, so the EBU has not bothered with general regulations, relying on specific regulations for those two events.

 

There have also been a couple of occasions in the European Championships where one particular country's team has not arrived at the venue until the second match.

We hope :rolleyes: the EBL has adequate regulations.

[bluejak]

I am fully aware that events outside Norway need not bother about Norwegian routines or regulations, but frankly: I don't see the problem, whether in Norway or anywhere else!

That seems to be what your whole problem is: lack of sympathy for other people's problems. Teams sit the same way: teams do not turn up: players may be at fault: TDs may be at fault: outside agencies may be at fault.

 

It is reasonable to ask for advice on this forum for such cases, and answers that they do not happen are unhelpful and naive.

[paulg]

The Scottish trials, which use this VP scale, state:

 

If, owing to lateness or some other reason, the Director determines that one or more boards have to be cancelled, then

1. Provided at least half a match can be played, an artificial adjusted score (A+ for nonoffender/ A- for offender) will be awarded for each unplayed board.
   
2. If less than half a match can be played, then the match is declared void and is scored:-
   1. 
      
   2. For a non-offending side
      The greatest of 16 VPs, their average VP match score, the complement of their
      opponent's average VP match score
      
   3. For an offending side
      The least of 12 VPs, their average VP match score, the complement of their
      opponent's average VP match score.
      

It used to be a minimum of 18 VPs for the non-offending side, but analysis of scoring trends in these competitions suggested that this was too much and unfair to the other participants.

 

It is not a contentious point, unlike much of the trials process :rolleyes:

[pran]

I am fully aware that events outside Norway need not bother about Norwegian routines or regulations, but frankly: I don't see the problem, whether in Norway or anywhere else!

That seems to be what your whole problem is: lack of sympathy for other people's problems. Teams sit the same way: teams do not turn up: players may be at fault: TDs may be at fault: outside agencies may be at fault.

 

It is reasonable to ask for advice on this forum for such cases, and answers that they do not happen are unhelpful and naive.

I have answered:

- Teams sit the same way

- Teams do not turn up

- Players may be at fault

 

I have yet to imagine how a Director's error can result in a whole match becoming void and have never even heard of such a case during my more than thirty years of directing bridge.

 

So long as the question is "what score do we award to a team who's match is void because of a Director's error" I need to have an example on how this can happen before I can present any useful answer.

 

I resent any accusation of lack of sympathy for other people's problems when I do not even know what the problem is supposed to be. Show me a possible realistic case instead of throwing dirt with unfounded accusations and I shall be ready to comment.

[jallerton]

The original question is a strange one.  We do not award Ave+ or Ave- in VPs: read Law 12C2.

Sorry if I used the wrong terminology. How many VPs do you assign to a team when none of their match can be played and they are in no way at fault?

Now the question becomes simple. That is a matter for regulation, and any organisation that does not have such a regulation is at fault.

 

The EBU does not worry too much about the 25-0 scale since they rarely use it, but have a general regulation of 1.5 imps a board.  That is probably too generous, and leads to a win of between 19 and 23 VPs: that is too many.

The EBU uses the 25-0 scale for the Premier League and the final of Crockford's, which are two of England's most prestigious events. It is quite common for players to turn up late for bridge events, and when motorways are shut and railway lines become blocked it is not unknown for a journey delay to be more than the scheduled length of the first match.

The fact that they are prestigious is irrelevant: the point is that the scale is used rarely, so the EBU has not bothered with general regulations, relying on specific regulations for those two events.

In fact, the EBU does seem to have regulations other than the 1.5 imp/board rule that you mention.

 

The EBU White Book suggests that the VP score for the "not at fault" participant depends on the reason for not being able to play the match.

 

147.6 Incorrect seating in a teams game

Suppose the teams sit incorrectly, such that an entire stanza or match is made void.

Note If the incorrect seating at one table is identified before team-mates play the

same boards, this error is easily rectified without cause to penalise either

team, by arrow-switching the boards once they are exchanged.

If time permits, the stanza or match must be replayed forthwith in which case neitherteam is penalised. This is normal in a knockout tournament. If time does not permit he replay of the stanza/match, then:

[snip]

(d) if the TD is responsible for the incorrect seating of the teams, then the

teams score the converse of the above (this award is not over-generous

and assumes the teams concerned to be partially at fault for the error); eg

12 VPs out of 20 instead of 8;

(e) where a 25 to 0 scale is used this is in effect a 20 to 0 scale with 5 added to

both sides. So average is 10 plus 5, 13 as in (B) above is 8 plus 5, and the

converse as in (d) would be 12 plus 5, ie 17;

 

145.2 All Play All event - withdrawal

If a contestant withdraws before half of the event is completed, all scores obtained

against that contestant are cancelled.

If a contestant withdraws after half of the event is completed, all scores obtained

against that contestant stand. Opponents who cannot now play that withdrawn

contestant receive the best score from the following (any fraction resolved upwards to

the minimum unit of scoring):

(a) their own average over the entire competition;

(B) the converse of the withdrawn opponents' average over the competition so

far;

© in a contest scored by victory points;

12 VPs on a 20 to 0 scale

6 VPs on a 10 to 0 scale

7.5 VPs on a 12 to 0 scale

17.5 VPs on a 25 to 0 scale

 

What I can't understand is why the same algorithm isn't used in the two cases. In both situations the team has been denied its opportunity to play the match through no fault of its own, and hence I suggest that they be made the same in the final version of the 2010 White Book .

[jdonn]

I think whatever guideline is used should indeed be very generous to any team not at fault. They lost their chance to win by more and that is not fair to them at all. Giving them 18 victory points is almost nothing when their starting point is 15, I find that much more outrageous (in the opposite direction) than giving them 25.

Well, I do not. In the same way that Ave+ on a board is not 100%, I think it is very unfair to give a team a 100% score when they have not played.

 

I wonder how keen teams would be to play in difficult circumstances not caused by themselves if they get 100% for not playing? Splitting headaches would become routine. B)

I hope I don't need to say why any comparison to matchpoint scoring makes no sense.

 

And of course if I get a splitting headache and decide I can't play, my team isn't "not at fault". B) Well maybe fault isn't the right word, but I'm certainly responsible for the consequences of my own headache.

[gnasher]

the complement of their opponent's average VP match score

That seems a rather sloppily drafted regulation. Shouldn't it be the average of the complements of the opponent's VP scores?

 

If the opponents have played three matches, scoring 0, 0 and 11, my expectation is

  mean(25,25,19) = 23

but the complement of mean(0,0,11) is 25.