10. A computer program product, comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to perform a method comprising: generating, using a processor of the computer, a binary decision model by training a binary classifier using a plurality of training documents; classifying, using the processor, one or more test documents into one of a plurality of document type categories using the binary decision model, wherein the one or more test documents lack a user-defined category label; selecting, using the processor, a most relevant example of the classified test documents from among the classified test documents, wherein the most relevant example of the classified test documents is the test document having a classification score closest to a boundary between a positive decision and a negative decision concerning the test document belonging to a particular one of the plurality of categories; displaying, using a display of the computer, the most relevant example of the classified test documents to a user; receiving, via the computer and from the user, a confirmation or a negation of a classification label of the most relevant example of the classified test documents; and storing the confirmation or the negation of the classification label of the most relevant example of the classified test documents to a memory of the computer.
12. The computer program product of claim 10 , wherein the only response options for the user to provide, in response to reviewing the displayed most relevant example, are the confirmation and the negation.