1. A system comprising: a computer comprising a memory device and a central processing unit (CPU); application software; means to read a set of in-sample examples into the memory device of the computer; means to specify a partition of the in-sample examples into a validation set and a remaining set; means to specify a partition of the validation set into two holdout sets, a first holdout set and a second holdout set; means to compute the frequency, over the validation set, of inputs for which the classifier based on the remaining set is incorrect; means to compute the difference in two frequencies over the second holdout set, the first frequency being of inputs for which the classifier based on the remaining set is correct but the classifier based on both the remaining set and the first holdout set is incorrect, the second frequency being of inputs for which the classifier based on the remaining set is incorrect but the classifier based on both the remaining set and the first holdout set is correct; and means to compute the difference in two frequencies over the first holdout set, the first frequency of inputs for which the classifier based on the remaining set is correct but the classifier based on both the remaining set and the second holdout set is incorrect, the second frequency of inputs for which the classifier based on the remaining set is incorrect but the classifier based on both the remaining set and the second holdout set is correct.