Methods and devices, including methods and devices for estimating classifier performance such as generalization performance, are disclosed. One method includes providing multiple samples. Each sample is characterized by one or more features. This method also includes associating a feature variability with at least one of the one or more features; and computing a first probability of misclassification by a first classifier using the feature variability. Devices, including integrated circuits (ICs) and field programmable gate arrays (FPGAs), that are configured for use in carrying out the present methods are also disclosed.