1. A computer-implemented multi-stage classification system that facilitates reducing human effort in text classification while obtaining a desired level of accuracy comprising: one or more processors; memory, accessible by the one or more processors; a pattern-based classifier component stored in the memory and executable on the one or more processors to assign the input a label assign a label to the input, and to build one or more suffix arrays over a subset of text from the set of training items to determine correlation between each pattern of a plurality of patterns and the label, the pattern-based classifier component to classify the input as having a pattern of the plurality of patterns when a corresponding correlation satisfies a correlation threshold the set of training items comprising at least one of text documents, messages, and files that are each labeled based on one or more text patterns; and a learning-based classifier component stored in the memory and executable on the one or more processors to process the input for classification when no label is assigned to the input by the pattern-based classifier component.