1. A classification count adjustment system comprising: a computer-readable storage medium to store: a count estimate produced by a classifier of a number of items in a dataset that have been classified into a class; one or more measures of behavior of the classifier indicating an ability of the classifier to classify the items into the class; a processor for computing an adjusted estimate based on the count estimate by the classifier and the one or more measures of behavior; and a reporting module to output the adjusted estimate for use in determining an amount of items that belong to the class.