Source: Justin Lall
Most auctions start with each partner describing their hand to the other until one of them is able to take control. Taking control sometimes involves asking specific questions (such as blackwood) and sometimes just means placing the contract. When it comes time to place the contract I find the most effective thing to do is mental hand simulation. Things like combined high card point and losing trick count are now irrelevant as you should have enough information to figure out a range of hands for partner. From that you can determine what is most likely to be the best contract.
Obviously there are time limitations and we are not computers so we can only construct a limited number of hands. To try and get the best range, I like to think of 5 hand types. Horrible minimums, perfect minimums, horrible maximums, perfect maximums and average hands. I like to try and make about 3 average hands and 1 of each of the others. This method that I use was mainly based off of something someone wrote in the Master Solvers Club. I’m fairly sure it was Jeff Rubens, but I could be wrong. Doing this you get a very good idea of where you stand.
Let’s try a few hands.
You hold 
AQ3 
AKJ2 
KQ62 
Q3 and open 2N 20-21. Partner bids 4NT inviting a slam and denying a 4-card major. You do not have any method to show 4-4 in the minors, so that shape is possible. At this point instead of thinking “I am maximum so I will bid slam” you should start constructing hands. To do this, we must consider what partner will have. He likely has about 11 points, possibly 12 with no 5 card suit or a very good 10. His possible shapes are 4333, 5332 with a 5 card minor, or 4432 with 4-4 in the minors. With a 6 card minor or 9 minor suit cards you have the methods to bid something besides 4NT. In your simulations you want to include all possible shapes.
Horrible minimum: KJx Qxx Ax Jxxxx. Here we are off the AK of clubs and have no play.
Perfect minimum: Kxx xx Axxxx Kxx. Here 6 is gin but 6N will be on a heart finesse.
Horrible maximum: KJx xxx Axx KJxx. With 2 clubs, 3 spades, 3 diamonds and 2 hearts there are 10 top tricks. If the heart hook works you need a red suit to split or have numerous squeeze chances.
Perfect maximum: xx Qxx AJxx KJxx. Here slam is very good, if diamonds split you are cold otherwise you can try a spade hook in 6 diamonds. In 6N you need spade hook or a black suit squeeze.
Average hand: Jxx Qxx Axxx AJx. In 6N we have 3 diamonds, 4 hearts, 1 club and 1 spade off the top. If the diamonds split we just need both black kings to not be offside. If diamonds don’t split we likely need a spade/diamond squeeze. 6 is worse.
Conclusion: I did these simulations hands just as I would at the table. I got every shape and HCP range in, and tried to spread the honors out as evenly as possible. On reflection one error I made was always giving partner the diamond ace. Had I done 3 average hands I probably would have given pard one with the spade king and club AK or something. This seems to be a very close case. It seems to come down to whether or not partner has a diamond fit. If I had 5 diamonds available to show 4 diamonds and be forcing, I would choose it. If partner signed off in 5NT I would pass, otherwise we would be going to slam. If not, I would probably bid 5NT pick a slam trying to get to 6 and otherwise play 6NT. Your simulations may come up with a different answer! Usually there won’t be discrepancies, but in a case this close there might be.
Let’s try one more. You open 1 and partner bids 3 showing a 4 card limit raise. Your hand is 2 AK532 QJ82 Q42. Partner will have about 10-12 support points and has a wide range of possible shapes.
Horrible minimum: KJx QJxx xx Kxxx. Game has no play here and even 3 is not cold.
Perfect minimum: xxx Qxxx KTx AJx. Game is just cold here barring something very bad happening.
The horrible mins and horrible maximums will be the same, all depending on how much wastage there is in spades.
Average hand: QJxx Qxxx Kx Kxx. Here is a normal 11 count with evenly distributed honors. With a loser in each side suit, we have a lot of play. To get rid of the minors we might pitch one on the spades get 2-2 hearts, get a favorable lead, or find the T9 of diamonds third.
Average hand: AQxx Qxxx x JTxx. We must think about unbalanced hands. If partner has a shortness it’s likely in diamonds. We have 2 clubs and a diamond to lose and a lot of work to do. They may get a club ruff or lead trumps. They don’t always defend perfectly though, and even when a ruff is available they may not find it.
Conclusion: Much depends on partner’s spade holding. With the average hands we saw game was close but not cold. I would bid this game at imps and hope for the best, but at matchpoints I would pass. If it is tough to make 4 we’ll get a good matchpoint score for 170, but it may just be a win 1 in imps.
Did that feel like hard work? Well it is, but it also will give you much more accurate results than thinking about whether you are minimum or maximum in your high card range. Remember, practice makes perfect and it does get easier.