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Proprietary Phonetic Algorithm - soundIT

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The API provides a unique phonetic algorithm for name matching, called soundIT.  soundIT takes account of vowel sounds and syllables in the name, and, more importantly, determines the stressed syllable in the word.  This means that "Batten" and "Batton" sound the same according to soundIT, as the different letters fall in the unstressed syllable, whilst "Batton" and "Button" sound different, as it is the stressed syllable which differs.  Another advantage of soundIT is that it can recognize groups of vowels and consonants that form vowel sounds – thus it can equate "Shaw" and "Shore", "Wight" and "White", "Naughton" and "Norton", and "Leighton" and "Layton" (which are all reasonably common English last names).

This algorithm was developed with extensive testing on a large table of the most common last names in the UK.  Therefore, it is specifically designed to be used with English names.  If a file with mostly non-English names is processed through the matchIT API, then you may want to try the ‘Loose’ soundIT or Soundex algorithms instead.  For US data we recommend that you use soundIT, because it is proven to work well also with Spanish, German and other names that occur commonly in the US.  soundIT has been designed with foreign language versions in mind (i.e. for data collected in countries where foreign languages are spoken).  These could quite easily be developed, according to demand.  Please contact your supplier if you are interested in this.

Note that the keys that the matchIT API generates are ‘Loose’ soundIT keys, where all vowel sounds are equated, together with some consonants, such as ‘m’ and ‘n’, ‘d’ and ‘t’, ‘s’ and ‘f’.  This is so that potential matches are not missed from candidate match groups based on the phonetic keys; The API uses the ‘full’ soundIT algorithm at the scoring stage, for matching accuracy.


While soundIT is reccomended in general, there are additional options available:

Loose soundIT

This option is effectively the same as the soundIT option, except that the API uses the ‘Loose’ soundIT algorithm as described above at the scoring stage.  This is for use mainly with non-English names, on which soundIT works less effectively, and can miss True matches.  This option should not be used on files with mainly English names, as it can potentially lead to more false matches.

Dynamic soundIT

This is a hybrid of the soundIT and Loose soundIT phonetic algorithms. Firstly, the loose algorithm is used to generate the phonetic form of a word. By default, if it contains only one vowel sound, then the standard soundIT algorithm is used instead. This can improve accuracy when matching mono-syllabic words and can help to reduce the number of false matches.


Soundex is a widely-used algorithm (patented just after the First World War!), which constructs a crude non-phonetic key by keeping the initial letter of the name, then removing all vowels, plus the letters H, W and Y, and translating the remaining letters to numbers.  It gives the same number to letters that can be confused e.g. ‘m’ and ‘n’ both become 5.  It also drops repeated consonants and consecutive letters that give the same number e.g. S and C.  It only takes the first four characters of the result, or pads it out with zeroes if it is less than four long.  Thus all the common spellings and misspellings of the name "Tootill" equate to the same Soundex key: Tootill, Toothill, Tootil, Tootal, Tootle, Tuthill, Totill are all translated to "T340".

The algorithm that the matchIT API uses is an enhanced version of Soundex, and is for use mainly with non-English names.  This option should not be used on files with mainly English names, as it can lead to False matches e.g. Brady, Beard and Broad get the same Soundex key.

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