This is the ARCHIVE website for Mountnessing Bridge Club
2006 - 2015
For current news, results, etc please visit
http://www.bridgewebs.com/mountnessingbc/

Search This Site

BUTLER SCORED PAIRS EVENTS

Intoduction

Note that this page is aimed mainly at players who are not familiar with teams-of-four scoring, and its objective is to offer some background explanations and some 'helpful hints'.

The differences and similarities between a 'Butler-scored' pairs event and a traditional 'Match-pointed' pairs event

1. The movement of players and boards is exactly the same for the two types of events. Usually that means that the East / West pairs move around the room 'up one table' [i.e., from table 1 to 2, 2 to 3, etc,] and the boards move one table in the opposite direction. Only if the number of tables requires there to be a special movement is there any significant departure from the simple Mitchell movement. The number of tables in play determines the movement selected; the method of scoring has no impact.
2. In a match-pointed scored event, the 'match points' you score on a given board are based purely on positional relativity to the other scores. So, for example, if you are playing NS, and if the second best score for NS is +110, it would not make any difference if your own score was +120 or +1000 - either way you would score a 'top' on the board, simply because you scored better than all the other pairs playing in the same orientation as yourself. In a Butler-scored event, the absolute relativity is all-important, so you would score a lot more 'IMPs' for getting 890 more than the other scores rather than just 10 more.
3. Another difference is that there is a fixed number of total 'match points' available per board on a traditionally-scored Match-Pointed Pairs event - determined solely by the number of times the board is played. In a Butler-scored event, the total number of 'IMPs' scored on a board is variable, and will simply depend on the variability of the contracts and results, not on the number of times the board is played. If all the scores are identical, then all the IMPs scores will be zero, for example.
4. Another way of looking at the previous point is to say that in Match Pointed pairs every board carries equal 'weight' in the overall final rankings, but with Butler scoring, any particularly high, or low, score will have a big impact on your overall score and ranking.

Illustrative examples

How are the Butler scores calculated?

Supposing you are sitting NS on a particular board. The algorithm looks at all the scores on the board from a NS perspective; it ignores the single best score and the single worst score, and takes the average of all the rest. The result of that calculation is called the datum score. The IMP score you are awarded on the board is then deduced from the difference between the datum score and your own; if the difference is negative - i.e., your score was less than the datum - your IMP score will be negative. If the difference lies between +10 and -10 inclusive, your IMP score will be zero. There is a conversion table printed on every standard EBU Personal Scorecard - eg, as used at the club - that will enable you to convert the difference into the IMPS equivalent. You can then add up your IMP score over all the boards you play to give your pairing an overall total. Note that an overall IMP score of 0 is roughly equivalent to a 50% score at Match-Pointed scoring. But don't worry - the computer will do all these calculations for you!

EXAMPLE 1

		Match Pointed Scores		|	IMP Scores
Table number	NS Score	NS 'Match Points'	EW 'Match Points'	|	NS 'IMPs'	EW 'IMPs'
1	+170	6	12	|	-3	3
2	-50	2	16	|	-7	7
3	-100	0	18	|	-8	8
4	+170	6	12	|	-3	3
5	+170	6	12	|	-3	3
6	+420	12	-6	|	4	-4
7	+450	15	3	|	5	-5
8	+500	18	0	|	6	-6
9	+450	15	3	|	5	-5
10	-400	10	8	|	4	-4
				Butler Datum = 273

EXAMPLE 2

		Match Pointed Scores		|	IMP Scores
Table number	NS Score	NS 'Match Points'	EW 'Match Points'	|	NS 'IMPs'	EW 'IMPs'
1	+200	6	12	|	-6	6
2	+170	2	16	|	-7	7
3	-200	0	18	|	-12	12
4	+200	6	12	|	-6	6
5	+200	6	12	|	-6	6
6	+620	12	-6	|	4	-4
7	+650	15	3	|	5	-5
8	+1400	18	0	|	14	-14
9	+650	15	3	|	5	-5
10	-600	10	8	|	4	-4
				Butler Datum = 461

Observations

1. The scores on the two boards look completely different. For a start, it looks as though NS were vulnerable in example 2, but not in example 1
2. The match-pointed scores in the two examples turn out to be identical! The simple explanation is that the positional relativities are the same in both examples. NS at 8 gained the best score in both examples, though in Example 1 it was only 50 points higher than the equal 2nd scores of NS7 and NS9, whereas in Example 2 the differential was 750.
3. Similarly, NS 3 had the lowest score in both examples. All the other scores also have the same rank order between the two extremes.
4. The Butler scoring shows that in Example 2, NS 8, who appear to have defended the opponents' sacrifice bid very well, did much better than the pairs who bid and made the game contract, but note that the four pairs who bid and made the game all got roughly the same IMP score as each other, even though their actual board scores were a bit different from each other. These four pairs scored considerably better than those pairs who failed to bid the game, and there was an even greater differential compared with the achievements of NS 3, who evidentally bid too high and went off in something.
5. The pattern of IMP scores in example 1 is much the same as in example 2, except they are very much 'dampened' in Example 1. That is partly due to the difference in vulnerability, but mostly due to the fact that the extreme scores in example 2 were much more extreme.

Summary tips and hints for those not familiar with Teams-of-Four scoring

Players who regularly play both Teams and Pairs Bridge would acknowledge that the two different formats can impact on tactics deployed in bidding, Declarer Play, and Defence.

With Butler-scoring:

1. Overtricks hardly matter, but the difference between making and not making a contract can be very significant - especially if it is a vulnerable game or slam contract. As Declarer - play safe to make your contract; as Defender you might risk conceding an overtrick or two in order possibly to defeat a seemingly unbeatable contract.
2. Don't bid a risky 3NT when there is a much safer suit game contract available. The extra 10 points you might score for making the 3NT contract are not worth the risk.
3. Similarly, don't bid a risky major-suit part-score, when there is a safer minor-suit part-score available. For example, if 2D would be safe, then don't risk 2S as an alternative; if 2S fails to make, the board will score badly for you, but if 2S happens to make you would gain an insignificant amount.
4. Missing game contracts - and missing slams - can be very expensive, so you should tend to bid up rather than down. This comment applies even more strongly if the contract is vulnerable.
5. Avoid conceding a 'telephone number' penalty score (unless you are absolutely certain that your opponents can make a slam).
6. Avoid 'pushing' your opponents into a 'dodgy' game contract - they might make it!

Ladder Points

The same method as has been used for claculating ladder points for Teams of Four events will be used. Please see the explanatory notes.