1. A method for estimating performance of a classifier comprising: (a) providing multiple samples, each sample characterized by one or more features; (b) associating a feature variability with at least one of the one or more features; (c) using the classifier, computing one or more scores for one or more samples in a subset of samples from the multiple samples; (d) associating a score variability with at least one of the one or more scores using the feature variability; and (e) computing a probability of misclassification by the classifier using one or more of the one or more scores and the score variability.