1. A computer-implemented method for estimating performance of a classifier comprising: using suitably programmed hardware to associate a feature variability with at least one of one or more features that characterize a sample from multiple samples, each of which is characterized by one or more features; using the classifier to compute, with the hardware, one or more scores for one or more samples in a subset of samples from the multiple samples, where the classifier can be used to determine a class to which a sample belongs based on the one or more features that characterize that sample; using the hardware to associate a score variability with at least one of the one or more scores using the feature variability; computing, with the hardware, a probability of misclassification by the classifier using one or more of the one or more scores and the score variability; and outputting the probability of misclassification, or a score indicative of the probability of misclassification, to a user.