Cyberyeti, on 2018-November-17, 14:57, said:
At MPs they're more or less the same, but more people will bang down the ace, as stiff K is marginally more likely than void for W, if you want to create a swing, this is a decent place to try the safety play.
We can go even further. If a team match with matchpoints is played (where you can make only TOP, ZERO, or 50%), trying to drop the stiff king is definitely (mathematically) better than safety play. Definitely, but only slightly; so I'd ignore that. I know you'll agree (with the blue strategy), but for the sake of other readers:
If I played such a match, I'd try to make as educated guess as possible - what would my direct opponent (South from other team) do. If we have a lead in the match, I'd try to play same as him. If we're behind, I'd try to play differently than him.
But in big and heterogeneous field, I'd always chose to make the game (see below)...
Stephen Tu, on 2018-November-17, 15:32, said:
The gain of making the uptrick is smaller than the swing of making vs going down. But it's also more frequent. So it depends what percent are in the normal 4s vs say 5d-x down 3 or fewer.
Suppose we are playing field where 9 other tables play 4s, all playing for drop stiff k off, and one escaping for 5d successful sac. By playing safe instead of banging down ace you swing 5.5 points your way 10.53%, of the time. But you lose 4.5 mp 13.16%, which is a bigger number, so safety play is negative expectation in this case. But if only 70 percent of field was in 4s, the rest in contracts that 620 hearts, safety play would then win.
You've chosen a pretty small and very homogeneous field, so I can't disagree with you (though you couldn't claim even a 0.013 points advantage for chasing an overtrick - if you didn't count the fact that clubs are 3-3).
However, I am used to pair tournaments where every board is played by 15+ pairs, some of them players of international class, some of them (nearly) beginners. In such heterogeneous field, my experience is:
If you always make 620 in boards where -100 and 650 are also possible - your net result will absolutely and definitely be (well) over 50%.
(
I could elaborate why is that, but this post is already too long)
In the end, I'll just take a liberty to bring your attention to a certain direction:
In every deal, a percentage advantage (if exists) of chasing an overtrick is fixed, always the same. Points advantage of making a game (or slam) tends to grow in bigger and more heterogeneous fields...
Tramticket asks "You have arrived in a good contract. The defence start with ace and king of clubs, followed by a third club won in hand with the queen (or won in dummy with the knave if you prefer?).. At IMPs, you take the safety play for one loser in trumps. What do you do at Match-point Pairs (mixed field)?"
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IMO: Win ♣J in dummy and lead a ♠. If RHO follows, then cover his card.
As Cyberyeti points out, this safety-play loses when LHO has singleton King but he is almost equally likely to be void.
4♠ is an excellent contract and the first 3 tricks have relieved you of most of your worries.
Some pairs might under/over-bid, so It would be a pity to go down for a minus-score.