13. An apparatus comprising: at least one processor; and at least one storage medium having encoded thereon processor-executable instructions that, when executed by the at least one processor, cause the at least one processor to carry out a method of processing a plurality of expressions each having a medical meaning, each expression comprising a series of one or more words, the method comprising: extracting from a first expression at least one first clinical fact relating to the medical meaning of the first expression; extracting from a second expression at least one second clinical fact relating to the medical meaning of the second expression; determining whether the at least one first clinical fact and the second clinical fact have inconsistent medical meanings; and in response to determining that the at least one first clinical fact and the at least one second clinical fact have inconsistent medical meanings, determining a first series of one or more words related to the at least one first clinical fact, the first series being in the first expression and not in the second expression, determining a second series of one or more words related to the at least one second clinical fact, the second series being in the second expression and not in the first expression, and adding the first series and the second series to a set of series of words and associating the first series with the second series in the set.
13. An apparatus comprising: at least one processor; and at least one storage medium having encoded thereon processor-executable instructions that, when executed by the at least one processor, cause the at least one processor to carry out a method of processing a plurality of expressions each having a medical meaning, each expression comprising a series of one or more words, the method comprising: extracting from a first expression at least one first clinical fact relating to the medical meaning of the first expression; extracting from a second expression at least one second clinical fact relating to the medical meaning of the second expression; determining whether the at least one first clinical fact and the second clinical fact have inconsistent medical meanings; and in response to determining that the at least one first clinical fact and the at least one second clinical fact have inconsistent medical meanings, determining a first series of one or more words related to the at least one first clinical fact, the first series being in the first expression and not in the second expression, determining a second series of one or more words related to the at least one second clinical fact, the second series being in the second expression and not in the first expression, and adding the first series and the second series to a set of series of words and associating the first series with the second series in the set. 17. The apparatus of claim 13 , wherein the determining the first series of one or more words related to the at least one first clinical fact comprises: removing a removed word from the first expression to form a modified first expression; evaluating the modified first expression using a medical fact extractor to determine whether the modified first expression expresses the at least one first clinical fact; and when the modified first expression does not express the at least one first clinical fact, determining that the first series of one or more words related to the at least one first clinical fact comprises the removed word.