[rossdavidh]

You really would also want to have some sort of loss function, or at the very least a general idea of whether you most need to avoid false positives or false negatives. If it was most important to avoid incorrectly saying it's NOT a P&D, then this is not good performance. If you need it to nearly always avoid saying something which is not a P&D (and thus might be a great investment opportunity), but given that you want to avoid as many as you can, 50% might be good.