[ASkolnick]

I was trying to figure out the best way to combine IMPS and match point scoring since I can see flaws with each of them in a pair game.

Matchpoints:

Bad
+100 and +110 are essentially the same score.

Good
All hands are treated equally

Imps:

Exactly the opposite.

I was thinking of being able to combine them in the following way:

1) Matchpoint the Score.
2) IMP the score against the mean

Take the # of StdDev of both combined as your score.

Now for a question:

Would your play more like matchpoints or IMPS?

[Trinidad]

If you want to mix IMPs and MPs, my suggestion would be that you use the Patton format. This contains a conversion of the IMPs for the round to victory points. That means that you need to do the following:

- You play a number of boards per round (say 4)
- You MP each board
- You Cross IMP each board (normalized for the number of comparisons) (rather than IMPing against the mean).
- You add the MPs for all the boards in the round
- You determine the total IMP score for the round
- You convert the cross IMPs for the round to a victory point scale. This victory point scale is designed in such a way that the maximum number of VPs that can be gained in a round equals the maximum number of MPs that can be gained in a round. (This is a fixed number.)

This should be a pain to do by hand, but a scoring program could do it quite easily.

Just a quick example for 6 pairs, 4 boards (1-2, 3-4, 5-6):

Board 1 (results, MPs*, XIMPs): NV Game swing
1 +420, 4, +8
2 -420 0, -8
3 +170, 2, 0
4 -170, 2, 0
5 -50, 0, -8
6 +50, 4, +8

Board 2: Partscore battle
1 -110, 0, -5
2 +110, 4, +5
3 +110, 4, +4
4 -110, 0, -4
5 +50, 2, +1
6 -50, 2, -1

Board 3: VUL Slam decision
1 -1370, 2, -5
2 +1370, 2, +5
3 -1440, 0, -7.5
4 +1440, 4, +7.5
5 -690, 4, +12.5
6 +690, 0, -12.5

Board 4: Partscore battle
1 -140, 0, -3.5
2 +140, 4, +3.5
3 -110, 2, -2.5
4 +110, 2, +2.5
5 +110, 4, +6
6 -110, 0, -6

The scores for the round: (MPs, XIMPs)
1: 6, -5.5
2: 10, +5.5
3: 8, -6
4: 8, +6
5: 10, +11.5
6: 6, -11.5

The match 1-2 had an IMP difference of 11 IMPs. We use a 16 point VP scale for 4 boards. (I don't have that at hand, but I am coming up with something that I think might be reasonable.)

VP, IMP difference
8-8, 0-1 (including 1)
9-7, 1-5
10-6, 5-9
11-5, 9-13
12-4, 13-17
13-3, 17-22
14-2, 22-27
15-1, 27-34
16-0, 34+

This completes the score table for the round: (MPs, XIMPs, IMP difference, VPs, Total score)
1: 6, -5.5, -11, 5, 11
2: 10, +5.5, +11, 11, 21
3: 8, -6, -12, 5, 13
4: 8, +6, +12, 11, 19
5: 10, +11.5, +23, 14, 24
6: 6, -11.5, -23, 2, 8

In this case (3 tables, 4 boards per round), in each round 16 MPs and 16VPs can be won per round.

Rik

* I use the European standard for matchpointing for the US standard, just divide by 2. (But don't forget to divide the VP's by 2 too. )