A method and system for identifying a candidate subset of a data set comprises comparing suffixes of query field values to data field values of records in the data set. Sufficiently similar records are included in the candidate subset. Query field value suffixes may range in length from the query field value itself down to a minimum suffix length. The longest suffix may be processed first, and then successively shorter suffixes may be processed until a satisfactory number of candidates are identified. Entries in an index data structure derived from the data set may associate various suffixes found in the data set with individual records. The data structure entries may include record keys identifying records with data field values identical to the suffix and may also include suffix pointers identifying related data structure entries with suffixes similar to the entry's suffix.