Re^2: Fuzzy matching of text strings

[buttroast]

Soundex is a great tool, but in this case it is not doing anything. The reason the first four descriptions in your sample return the same soundex code is because they only processed the "Promess" portion of each record.

Basically:

1. Grab the first letter:

String: Promessa H...
Soundex: P

2. Remove all vowels in remaining string:

String: rmssH
Soundex: P

3. Condense duplicate letters:


String: rmsH
Soundex: P

4. Assign 3 digits from l-r based on following key:

1. b,p,f,v
2. c,s,k,g,i,q,x,z
3. d,t
4. l
5. m,n
6. r

String: rmsH
Soundex: P6 (6 is for r)

String: msH
Soundex: P65 (5 is for m)

String: sH
Soundex: P652 (2 is for s)

DONE AT 3 DIGITS!!! GO NO FURTHER.

If there are consecutive characters from the same group, such as in the name "Duck", (c and k are both in group 2), the resulting soundex would be D200 (zeros are added to pad right if we run out of letters to change to numbers).

In summary, soundex is not appropriate for longer strings comparison. If you use it, the following would all be grouped as P652:

Promessa National Bank
Promessing Fertilizer Company
Promessa High Spirits
Promessing With Me

Hope this clears up Soundex for everyone.