Problems with using double-dummy data

There are obvious problems using double-dummy data to determine valuations. The first is that it undervalues queens. Double-dummy, I can always make 3 tricks in the suit:

       KTx
       AJx

That's because, double-dummy, I always know where the queen is.

Similarly, when I hold:

       Kx
       AJ9

Double dummy, I can make 3 tricks whenever east has the queen or the ten - about 3/4 of the time. (If east has the ten and west the queen, I can lead the jack from hand, forcing west to cover, then finesse east's ten.)

Another example:

       K9x
       AT8x

I can always make 3 tricks in this suit, double-dummy, by first leading low to the nine, then, if that loses, guess where the second honor is, double-dummy.

There are cases where other holdings are over-valued:

       Kxx
       QJxx

We get three tricks, doubly-dummy, if the suit splits 3-3, or if the ace is in the hand with the shorter suit. But any single-dummy play must choose to play east for the Ax holding if he wants to keep the chance for 3-3 split.

Possible solution: Use Single Dummy Data

The possibility of using single dummy data is tantalizing, but it provides some tricky obstacles. Even if we have enough single dummy data, the final contract partly determines the number of tricks declarer will make - if I bid to a 3 spade contract, I might make only nine tricks due to a safety play, while if I bid to 4 spades, I might make 10 tricks. That's just one problem.

The auction also makes the problem not a "pure" single dummy problem. If you auction starts:

     Partner  You
     1D       1S
     2C       3NT

you are more more likely to get a heart opening lead, for example.

One possiblity is to have a simulation posit a double-dummy defense against a single-dummy analysis by a program like GIB. I have not been able to do this, so far; one of my list of tasks to do is to learn the single-dummy interface to GIB's bridge engine.