But how can BBO identify them? Some players complain & someone may look at them, but that is labour intensive.
Some signs of cheaters:
- monthly or longer average >60%
- always play with same few Ps
- exceptional defensive play
Could BBO discover them via a computer program? AND distinguish cheaters from good players?
Well, I suggest using a sieve to identify cheating pairs.
- consistent average >60% resulting from successful bidding and play
- play on defense is much better than when declaring, since on defense they know the entire distribution. "Better" means more tricks, either directly compared to other players playing the same hand/trump/declarer, and/or using GIB play as a yardstick. (even better if BBO can compare same hands, same suit trump, same declarer)
- on defense, 1st lead is more successful than other players's 1st leads, or is consistently GIB's choice for best results.
This should identify a few pairs which are very lucky. If they continue to be successful in the next week or month, this is a good indication that they may be cheaters.
Good players will make good plays both declaring and defending, so will escape the sieve.
Lucky players will "revert to the mean" in following results, so they were "just lucky" for that period of time.
Then a manual review can done, especially of hands identified where the defensive play was exceptionally good. Was the play obvious from the particular bidding? Or did it show knowledge of partner's hand?
Then those IDs can be banned
tOM