7.2.3 Taking Sacrifices

We’ve been discussing how the form of scoring can affect your decisions. This time we’ll look at how your decision whether or not to take a sacrifice bid changes at MP or IMP scoring.

Once again it comes down to the very basics of the scoring. At MP you gain for each score you beat, no matter by how much. At IMP scoring what matters is how much you beat the scores in the rest of the field. So, once again, let’s look at what we are risking and what we might gain.

Suppose the auction goes:

They	We	They	We
	1♥	3♠	4♥
?

This is a classic situation, they are vulnerable and you are not. If you assume their game is making, then you will be successful bidding 4♠ even if they double you as long as you go down 3 or less tricks. Their game is worth 620 or more, and the penalty for three down doubled but not vulnerable is 500. The big risk is that their game won’t make and that you are turning a positive into a negative score.

Let’s look at the MP situation first. We’ll assume they are making 4♥ and that you are going to lose 500 points in 4♠ doubled. Here are the potential scores for this situation from an 8-table game.

Table	Contract	By	Result	NS+	NS-	N-S MP	E-W MP
1	4♥	N	+1	650		7.0	0.0
2	4♥	N	=	620		5.5	1.5
3	4♥	N	=	620		5.5	1.5
4	4♠X	E	-3	500		3.5	3.5
5	4♠X	E	-3	500		3.5	3.5
6	4♠X	E	-2	300		2.0	5.0
7	3♥	N	+1	170		1.0	6.0
8	5♥	N	-1		100	0.0	7.0

So, the east-west pair goes from 1.5 to 3.5 out of a maximum of 7 for taking the sacrifice, losing only to those who were lucky enough for their opponents not to find the game, and the one pair whose opponents pushed on to 5♥. So their possible gains are 2.0 or 5.5 MP depending on whether or not the opponents can be pushed into a negative score.

Now supposing we have misjudged and our sacrifice is going down four, now the MP scores might look like this:

Table	Contract	By	Result	NS+	NS-	N-S MP	E-W MP
1	4♠X	E	-4	800		6.0	1.0
2	4♠X	E	-4	800		6.0	1.0
3	4♠X	E	-4	800		6.0	1.0
4	4♥	N	=	620		3.0	4.0
5	4♥	N	=	620		3.0	4.0
6	4♥	N	=	620		3.0	4.0
7	3♥	N	+1	170		1.0	6.0
8	5♥	N	-1		100	0.0	7.0

This time, the east-west pair goes from 4.0 to 1.0 out of a maximum of 7 for taking the sacrifice. They still have the possibility of going from 4.0 to 7.0 out of a maximum of 7 if their opponents are pushed into a negative score.

There’s one more possibility. They might not be making 4♥. Then the MP scores might look like this:

Table	Contract	By	Result	NS+	NS-	N-S MP	E-W MP
1	4♠X	E	-3	500		6.5	0.5
2	4♠X	E	-3	500		6.5	0.5
3	3♠X	E	-2	300		5.0	1.0
4	3♥	N	=	140		3.5	3.5
5	3♥	N	=	140		3.5	3.5
6	4♥	N	-1		100	1.5	5.5
7	3♥	N	-1		100	1.5	5.5
8	5♥	N	-2		200	0.0	7.0

In this case, we go from 5.5 to 0.5, almost a whole board when we are wrong. However, at MP it is just a board. The next one we can make up our score by making an extra trick on play or defense, or by playing in a major instead of a minor.

Now, let’s see what happens in a head-on IMP match if our teammates bid and make 4♥ for 620 at the other table and we bid 4♠ over the 4♥ bid here.

If we lose 500 in 4♠ doubled, we win 120 total points, for 3 IMPs.
If we lose 800 in 4♠ doubled, we lose 180 total points, for -5 IMPs.
If we win 100 in 5♥, we win 720 total points, for 12 IMPs.

On the other hand, if our teammates are going down in 4♥, for -100 at the other table, and we bid 4♠ over the 4♥ bid here, the scores are:

If we lose 300 in 4♠ doubled, we lose 400 total points, for -10 IMPs
If we lose 500 in 4♠ doubled, we lose 600 total points, for -12 IMPs.
If we lose 800 in 4♠ doubled, we lose 900 total points, for -14 IMPs.
If we win 200 in 5♥, we win 100 total points, for 3 IMPs.

Now it is looking as if our cost of being wrong is 5 to 14 IMPs, and our benefit for being right is 3 IMPs. Not a very attractive proposition! It is especially the case because you need to wait for another game-level swing to make up your 10 to 14 IMPs. If you steal one extra trick on the next five deals, you will still be way behind.

Conclusion: Sacrifice bidding is a more attractive tactic at MPs than at IMPs.