BULLET Using the Sound Coding Index

To find an individual name among the millions listed in the 1880, 1900, 1910, and 1920 censuses, you will use an indexing and filing system called the Soundex. The Soundex is a coded surname (last name) index based on the way a surname sounds rather than the way it is spelled. Surnames that sound the same but are spelled differently, like Smith and Smyth, have the same code and are filed together. The Soundex coding system was developed so that you can find a surname even though it may have been reorded under various spellings.
To search for a particular surname, you must first work out its code. Every Soundex code consists of a letter and three numbers, like S650. The letter is always the first letter of the surname. The numbers are assigned to the remaingin letters of the surname according to the Soundex coding guide.

Soundex Coding Guide

The number represents the letters
1 B P F V
2 C S K G J Q X Z
3 D T
4 L
5 M N
6 R

Disregard the letters A, E, I, O, U, W, Y, and H.

Most surnames can be coded using the following four steps. (For names with prefixes, double letters or letters side by side that have the same number on the Soundex coding guide, see "Additional Rules".)

STEP 1: On line 1, write the surname you are coding, place one letter in each box.
STEP 2: On line 2, write the first letter of the surname in the first box.
STEP 3: On line 1, disregarding the first letter, slash through the remaining letters A, E, I, O, U, W, Y, and H.
STEP 4: On line 2, write the numbers found on the Soundex Coding Guide for the first three remaining unslashed letters. Add zeros to any empty boxes. Disregard any additional letters.                                           
Examples of Soundex-Coded Names

Additional Rules

Names With Prefixes

If your surname has a prefix - like Van, Von, De, Di, or Le - you should code it both with and without the prefix because it might be listed under either code. The Surname VanDevanter, for example, should be coded in the two ways shown. (Mc and Mac aer not considered prefixes).

Names With Double Letters

If your surname has any double letters, they should be treated as one letter. Thus, in the surname Lloyd, the seond L should be slashed out; in the surname Guiterrez, the second R should be slashed out.

Names With Letters Side By Side That Have the Same Number On the Soundex Coding Guide

Your surname may have different letters that are side by side and have the same number on the Soundex Coding Guide: for example, PF in Pfister (1 is the number for both P and F); CKS in Jackson (2 is the number for C, K, and S). These letters should be treated as one letter. Thus, in the name Pfister,F should be slashed out; in the name Jackson, K and S should be slashed out.

Names of Native Americans, Asians, and Nuns

Researchers using the Soundex system to locate nuns, or persons with native American or Asian names should be aware of the way such names are coded. Variations in coding differ from the normal coding system.

Phonetically spelled Asian and Native American names are sometimes coded as one continuous name, or, if a distinguishable surname is given, the names are coded in a normal manner. For example, the Native America name Shinka-Wa-Sa may be coded as "Shinka" (S520) or "Sa" (S000). researchers should investigate the various possibilities of coding such names.

Nun names are coded as if "Sister" was their surname, and they appear in each State's Soundex under the code "S236". Within the State's Soundex Code S236, the names are not necessarily in alphabetical order.

If several surnames have the same code, the cards for them are arranged alphabetically by given name. There are divider cards showing most code numbers, but not all. For instance, one divider may be numbered 350 and the next one 400. Between the two divider cards there may be names coded 353, 350, 360, 365, and 355, but instead of being in numerical order they are interfiled alphbetically by given name.

With your ancestor's name correctly coded, you are ready to use the microfilmed Soundex card index, which is organized by state, and thereunder Soundex code number, and thereunder alphabetically by first name or intial. There are four types of index cards. The information you should copy from each is on the next page.

Compiled by the History and Genealogy Department
1301 Olive Street
St. Louis, Missouri, 63103
(314) 539-0385

Revised August 1997, Reprinted July 1995

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