The Soundex is a system designed by the Works Project Administration to phonetically index surnames. In the days when nearly all of the data for the Census of Population was collected by actual enumerators and individuals who walked from door to door, it was discovered that many of these people spelled surnames phonetically. Thus, one might spell Smith as "Smith" while another might spell it as "Smyth" and still another "Smythe."

To improve the ease of accessing information, a card index was created--the Soundex. The cards give name, race, month and year of birth, age, citizenship status, place of residence by state and county, civil division, and, where appropriate for urban dwellers, the city name, house number, and street name. The cards also list the volume number, enumeration district number, and page and line numbers of the original schedules from which the information was taken.

Three types of cards were prepared: household cards, individual cards, and cards from institution, military posts, naval stations, and U.S. flag vessels. They were arranged by state or territory (a separate microfilm publication for each) and there under by the Soundex system (i.e. alphabetically by the first letter of the surname, and thereunder alphabetically by the first name. A guide for use of the Soundex system is reproduced below.

The Soundex filing system, alphabetic for the first letter of the surname and numeric thereunder as indicated by divider cards, keeps together names of the same and similar sounds but of variant spellings.

To search for a particular name, you must first work out the code number for the surname of the individual. No number is assigned to the first letter of the surname. If the name is Draughon, for example, the index card will be in the "D" segment of the index. The code number for Draughon, worked out according to the system below, is 625. Thus, the Soundex number is D625.

   Code                  Key Letters and Equivalents                    
        1                        b, p, f, v 

        2                        c, s, k, g, j, q, x, z  

        3                        d, t  
                  
        4                        l 

        5                        m, n 

        6                        r 

Rule 1. The letters a, e, i o, u, y, w, and h are not coded.

Rule 2. The first letter of a surname is not coded.

Rule 3. Every Soundex number must be a three-digit code. (Zeroes are used when necessary to make the code number have three digits.)

Example:Lee = L000 since the name yields no code number.

Example:Cook = C200 since only the letter "k" has a code value (2).

Example:Cline = C450 since only the letters "l" and "n" have code values.

Example:Icenogle = I252 NOT I2524 (Since all code numbers have only three digits -- no more, no less!)

Rule 4. If two letters or code equivalents appear together, or one key letter immediately follows or precedes an equivalent, the two are coded as one letter, by a single number.

Example: Kelly = K400

Example: Buerck = B620

Example:Lloyd = L300

Example:Schaefer = S260

Rule 5. If several surnames have the same code, the cards for them are arranged alphabetically by given name.

Other coding examples are: Kirkley (r, k, l) = K624; Drexler (r, x, l) = D624; Allricht (l, r, c) = A462; and Eberhard (b, r, r) = E166.