Minitinous Trump Break

[barmar]

I'm no statistician and would be happy to hear from someone who is, but your argument doesn't convince me: the probability of a given deal is identical to that of any other deal, but that does not mean that any set of deals is equally random however the hands were generated.

If the deals are generated independently, I don't think there should be any difference between the randomness of an individual deal and that of the set of deals.

 

The only question here is whether, when creating Best Hand deals, and the original random deal has the best hand in West, for instance, it makes a difference whether you swap West with South or rotate W->S, S->E, E->N, N->W. I don't think it should matter, because any permutation of the other 3 hands is equally likely.

[barmar]

The ACBL began using Big Deal for the Winter NABC in 2016. Nicolas Hammond (author of the recent Detecting Cheating in Bridge) proved that feeding a suitable program boards 1, 2, & 3 of an ACBL generated board set would yield boards 4-36 in a short enough time for the result to be useful for cheating on most of the "solved" boards. He also delivered statistics indicating that some pairs might be using this "crack" (or one like it) to cheat at NABCs and Regionals. The ACBL (and EBU, and USBF, and WBF) finished switching to Big Deal by January 2017.

We're less concerned about this kind of problem on BBO. The above crack depended on the fact that all the deals in a particular session were generated sequentially starting from the same seed. But the BBO dealer is generating hands concurrently for tournaments and regular bridge tables, so it's hard to discern the sequence of hands.