Fuzzy matching is a method used in some computer programs, most notably those designed to automatically translate text between different languages. It works in situations where the database used by the software does not have an exact match for a piece of text. Instead, the database looks for close matches, with human revision usually checking that this match is acceptably accurate.
Most automated translation programs simply compare text to a database of previous translations. This database is usually known as a translation memory (TM). Each new and confirmed translation is added to the database, meaning that future translations are usually more accurate and quicker.
Normally, TM-based translation works with entire sentences. For example, if a user has previously approved a particular sentence in French as being an accurate translation of, "The shop is open between 9 a.m. and 5 p.m. on weekdays, but closes at 2 p.m. on Wednesday," then the next time the software is asked to translate that sentence, it will automatically use the same French wording as before.
The fuzzy matching tool works with situations where a particular phrase has not come up in documents translated by the system before. The tool involves either the creator of the software or the end user setting an acceptable fuzzy matching level in the form of a percentage match. If the phrase is close enough to one previously translated to meet this percentage match, the software will advise the user of the match, give the previous translation, and ask the user to confirm or edit the proposed translation.
To follow up the previous example, if the fuzzy matching threshold was set at 90% and the new English document contained the sentence, "The shop opens between 9 a.m. and 5 p.m. on weekdays, but closes at 2 p.m. on Wednesday," the software would suggest the previously used translation and the user would likely click to approve it. If the new document had the sentence, "The shop is open between 9 a.m. and 5 p.m. on weekdays, but closes at 2 p.m. on Thursday," the software would suggest the previously used translation and the user would correct this translation to conclude with the French word for Thursday. If the new document had the sentence, "The shop is open from 9 a.m. to 5 p.m. on every weekday except Wednesday, when it shuts at 2 p.m.," the software would not consider this a fuzzy match, despite the meaning being the same, and thus would not offer an automatic translation for the sentence, leaving the user to translate it manually.