1. A computer-implemented system for providing visual suggestions for cluster classification, comprising: a cluster module to obtain one or more clusters comprising uncoded documents from a set, each cluster associated with a visual representation; a designation module to designate a different set of reference documents that are each classified with a code, each code associated with a visual representation different from the representations of the clusters and from the representations of the remaining classification codes; a cluster center module to identify a cluster center in one of the clusters comprising the uncoded documents and to compare the cluster center to one or more of the reference documents; a similarity module to identify those of the reference documents that are similar to the cluster based on the comparison; and a representation module to provide a visual suggestion for assigning one of the classification codes to the cluster comprising the cluster center by displaying the visual representation of the cluster comprising the cluster center together with a list of all of the reference documents similar to the cluster and the visual representations of the classification codes of each of the similar reference documents in the list.
3. A system according to claim 1 , further comprising: a spine module to determine a similarity between the clusters and to organize the clusters along one or more spines based on the similarity, each of the spines comprising a vector; a spine vector module to identify cluster centers for all of the clusters along one of the spines and to generate a score vector for the spine based on the cluster centers; a reference document vector module to generate score vectors for the reference documents based on content of the reference documents; a comparison module to compare the score vector for the spine to the score vectors for the reference documents and to identify those of the reference documents that are similar to the spine based on the comparison of the spine score vector to the score vectors of the reference documents; a spine classification module to visually represent the classification codes of each of the reference documents similar to the spine as a suggestion for assigning one of the classification codes to the spine.