1. A system comprising: one or more processors; and memory that stores instructions that are executable by the one or more processors to cause the system to perform operations comprising: receiving a first output of a categorization process applied to a training subset of documents of a plurality of documents, the first output including a first indication and a second indication for each document in the training set of documents, the first indication indicating a relevance between a document in the training set of documents and an issue in a set of issues and the second indication indicating a lack of relevance between the document and the issue; generating a classifier based at least in part on the first output; executing the classifier on the plurality of documents to determine a second output, the second output indicating an extent of relevance of each document in the plurality of documents to the issue; partitioning individual documents in the plurality of documents into subsets of documents based at least in part on the second output; adding additional documents from at least one subset of the subsets of documents into the training subset of documents to generate a control subset of documents; executing, as part of a first iteration, the classifier on the control subset of documents to determine a third output; determining, based at least in part on the third output, a threshold associated with the classifier, the threshold being associated with a cutoff point for binarizing a ranking of individual documents in the control subset of documents; computing, based at least in part on the cutoff point, a quality criterion associated with the classifier; determining, based at least in part on the quality criterion, a first quality of performance of the classifier as applied to the control subset of documents; receiving an input; determining, based at least in part on the input, to initiate a second iteration; determining a second quality of performance of the classifier for the second iteration; and displaying a comparison of the first quality of performance and the second quality of performance.