Section 2.4 - Guide to the Soundex System
American Soundex Codes
Many of the Indexes to the passenger lists use the Soundex system in listing the passenger's name. You must first find the Soundex code for your immigrant ancestor in order to use these indexes.
This system, which is also used for census indexes, keeps together names of the same and similar sounds but of variant spellings. To search for a particular name, you must first find the Soundex code number for the surname of the individual.
To find the Soundex code, you may use the "Soundex Calculator"
You can also find the code by following procedure. Use the first letter of the surname - No number is assigned to the first letter of the surname. If the name is Kuhne, for example, use "K''. The following letters of the surname are replaced with numbers in accordance with the following guidelines.
The first letter of the surname is retained and is followed by a three-digit code as worked out from the following equivalents. The letters a, e, i, o, u, y, w, and h are not coded.
Soundex Coding Guide
Number | Represents the Letters |
1 | B, F, P, V |
2 | C, G, J, K, Q, S, X, Z |
3 | D, T |
4 | L |
5 | M, N |
6 | R |
(The code number for Kuhne, worked out according to this system is K-500.)
Every Soundex number must be a three-digit number. A name yielding no code numbers, as Lee, would be L-000; one yielding only one code number would have two zeros added, as Kuhne, coded as K-500; and one yielding two code numbers would have one zero added, as Ebell, coded as E-140. Not more than three digits are used, so Ebelson would be coded as E-142, not E- 1425.
When two key letters or equivalents appear together, or one key letter immediately follows or precedes an equivalent, the two are coded as one letter, by a single number, as follows:
Such prefixes to surnames as "van,''
"Von,'' "Di,'' "de,'' "le,'' "Di,'' "D','' "dela,'' or "du'' are
sometimes disregarded in alphabetizing and in coding.
Other Soundex Coding Systems
The following systems of Soundex are
being offered as options on a number of online sites.
Daitch-Mokotoff Soundex
(D-M Soundex) is a phonetic algorithm invented as a
refinement of the American Soundex algorithms. It is
designed to allow greater accuracy in matching of Slavic
and Yiddish surnames with similar pronunciation but
differences in spelling.
To address the large number of false positive results generated by the D-M Soundex, the Beider-Morse Phonetic Name Matching algorithm. This new algorithm cuts down on false positives at the expense of some false negatives. A number of sites are offering the B-M soundex in addition to the D-M soundex.