1. A non-transitory computer-readable storage medium, the storage medium comprising computer instructions for: generating a historical database by extracting information from an on-line database according to selection criteria; extracting historical data from the historical database according to predetermined extraction criteria; searching for one or more potential duplicate entries in the historical data according to a portion of the selection criteria used for generating the historical database, wherein the potential duplicate entries arise from anomalies in the generation of the historical database; submitting a notification when one or more potential duplicate entries have been identified; accessing an exclusion list; and excluding from the searching one or more acceptable duplicate entries as identified by the exclusion list.