Paar | Contract | Res. | Score | XIMPS | ||

NZ | OW | NZ | OW | |||

1 | 3 NT | C | +600 | -1 | ||

2 | - 1 - | -600 | +1 | |||

3 | 3 NT | C | +600 | -1 | ||

4 | - 3 - | -600 | +1 | |||

5 | 3 NT | C | +600 | -1 | ||

6 | - 5 - | -600 | +1 | |||

7 | 3 NT | +1 | +630 | +4 | ||

8 | - 7 - | -630 | -4 | |||

9 | 3 NT | C | +600 | -1 | ||

10 | - 9 - | -600 | +1 |

Let us consider the example we used before. In a contest of 10 pairs the contract is 3NT at all tables. Everyone
just makes this contract, except one pair who make an overtrick. At MP's this meant a top (8 MP, and a 0 for the
opponents.

At cross-IMPs there are 4 scores to compare with, each of them yielding 1 IMP, for a total score 4 for
the pair who managed to get an overtrick, and -4 for their opponents.
At the other tables all pairs score +1 or -1 IMP. Pairs who play in the same compass direction as the one strong pair
score -1, 1/4 of the score of the pair who had a direct encounter with the strong pair.

You probably have already identified the number 4 (i.e. the number of comparisons on which the cross-IMP score is based)
as *h*, half a top at MP-scoring, or, the number of times - 1 the hand is played. Again we notice that the effect
of a direct encounter is *h* times as large as playing in the same compass direction.
This is equally true whether the difference is one trick, as in this example, or whether we have a swing hand where both sides
can make game. Also, it does not matter whether or not the Cross-IMP score is calculated as an average, i.e. the XIMPS we
used here
divided by the number of times
a hand is played. In all cases we have:

Also in cross-IMPs playing once against an opponent is equivalent to *h* times playing in the same compass direction.
The techniques we used to obtain an optimal balance are also valid for cross-IMPs.

Conclusion: For cross-IMPs just use the same movements as for MP's.