11. A system for displaying relationships between concepts to provide classification suggestions via nearest neighbor, comprising: a database to maintain reference concepts each associated with a classification code and a set of uncoded concepts, wherein each of the reference concepts and the uncoded concepts comprises one or more nouns extracted from a plurality of documents; an association module to associate each reference concept with a symbol representing the classification code; a similarity module to compare at least one uncoded concept with the reference concepts and to identify one or more of the reference concepts that are similar to the at least one uncoded concept; a display to display relationships between the at least one uncoded concept and the similar reference concepts for classifying the at least one uncoded concept based on the classification symbols of the similar reference concepts comprising at least one of: a presence module to display one or more of a presence and absence of the similar reference concepts with different classification codes; and a quantity module to display a quantity of the similar reference concepts for each of the different classification codes; a suggestion module to provide at least one visual classification suggestion based on the displayed relationships; a classification module to receive a classification code for the at least one uncoded concept from a human reviewer based on the at least one suggestion; and a computer processor to execute the modules.
11. A system for displaying relationships between concepts to provide classification suggestions via nearest neighbor, comprising: a database to maintain reference concepts each associated with a classification code and a set of uncoded concepts, wherein each of the reference concepts and the uncoded concepts comprises one or more nouns extracted from a plurality of documents; an association module to associate each reference concept with a symbol representing the classification code; a similarity module to compare at least one uncoded concept with the reference concepts and to identify one or more of the reference concepts that are similar to the at least one uncoded concept; a display to display relationships between the at least one uncoded concept and the similar reference concepts for classifying the at least one uncoded concept based on the classification symbols of the similar reference concepts comprising at least one of: a presence module to display one or more of a presence and absence of the similar reference concepts with different classification codes; and a quantity module to display a quantity of the similar reference concepts for each of the different classification codes; a suggestion module to provide at least one visual classification suggestion based on the displayed relationships; a classification module to receive a classification code for the at least one uncoded concept from a human reviewer based on the at least one suggestion; and a computer processor to execute the modules. 18. A system according to claim 11 , further comprising: a concept similarity module to determine the similar reference concepts, comprising: a vector module to form a score vector for each uncoded concept and each reference concept; and a similarity measurement module to calculate a similarity metric by comparing the score vectors for the at least one uncoded concept and each of the reference concepts and to select the reference concepts with the highest similarity metrics as the similar reference concepts.