1. A computer-implemented method, comprising: computing, based at least in part on a plurality of historical records, a set of inverse document frequencies corresponding to a set of search terms associated with a request to determine a user identity; for at least a subset of the plurality of historical records, the subset of the plurality of historical records corresponding to the set of search terms, determining a set of search term results that each indicate an extent to which a search term of the set of search term results corresponds to at least one historical record of the subset of the plurality of historical records; filtering, based at least in part on the set of inverse document frequencies and the set of search term results, the subset of historical records to obtain a subset of the subset of the plurality of historical records; passing inverse document frequencies of the subset of the subset of the plurality of historical records through a random forest to obtain a set of confidence scores, each confidence score of the set of confidence scores corresponding to a historical record of the subset of the subset of the plurality of historical records; and determining a user identity associated with a historical record based at least in part on the set of confidence scores.