1940 Occupation, Industry, and Class of Worker Coding and Verification

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[Excerpted from Robert Jenkens, "Chapter Four - Processing and Tabulation," Procedural History of the 1940 Census of Population and Housing, Madison, WI: The Center for Demography and Ecology, University of Wisconsin, 1983, pp. 75-78.]

Operation 9 consisted of the coding of occupation, industry, and class of worker entries on the population schedule, columns 28-30, F, 45-47, J, and U. The Operation 9 instructions are reproduced in Appendix IV. In the preparations for this coding an occupation index was prepared in two volumes: a Classified Index with more than 25,000 occupational designations arranged according to occupation or occupation group, and an Alphabetic Index of the occupational designations indicating to which of the 451 occupations and occupation groups the classification belonged.1 The Alphabetic Index also included approximately 9,500 industry designations and symbols indicating to which of 132 titles of the industry classification the designations belonged. This index was prepared by Dr. Alba M. Edwards, with assistance from Ernest J. McCormick, and was based upon the Standard Industrial Classification developed under the auspices of the Central Statistical Board between 1937 and 1939.

Each occupation coding clerk was provided with a copy of the Alphabetic Index of Occupations and Industries and a Large card, "List of Principal Occupations and Industries with their Symbols," on which several of the principal occupations and industries in the index were printed. These coding aids were used to look up each entry of an occupation (column 28) and of an industry (column 29). The symbols given in the Index for each were entered in the first two sections of column F of the schedule. In addition, columns 45 and 46 of the "Supplementary Questions" section of the schedule were coded according to the instructions for coding columns 28 and 29. Only those persons who were considered to be in the labor force were given occupation, industry, and class of worker codes. Such persons were determined by the codes appearing in column E ( for a description, see above, page 14). Only persons with column E codes of "1," "'2," "3," or "4" were considered to be in the labor force.

An "occupational designation" consisted of a complete return of an occupation of the person and the industry, business, or place in which the person worked. Each occupational designation was represented in the Alphabetic Index by a five digit code symbol. The first three digits of the code indicated the occupation and the last two digits represented the industry. In cases in which an occupation occurred in many industries, the code for the industry in the occupational designation was "Ind.," indicating that the code for the particular industry listed in the Industry Index was to be used.

The entry in column 30 of the schedule was for class of worker. These entries were coded in the third space in column F, according to the following scheme:

Schedule Entry Code Meaning
PW 1 Wage or salary worker in private work
GW 2 Wage or salary worker in government work
E 3 Employer
OA 4 Working on own account
NP 5 Unpaid family worker
New worker 6 Person without previous work experience

Coders were instructed to consider as unpaid family workers all children under 18 years of age and women of any age who were enumerated with their family on a farm and returned as farm laborer, garden laborer, or other agricultural laborer, with no entry for column 30, unless there was information indicating otherwise. All other persons returned as farm laborer, garden laborer, or other agricultural laborer, with no class of worker entry were coded as wage or salary worker in "private work." Coders were also instructed to check the occupation entries of "farmer" and "farrn laborer" to see that they were consistent with the entry in column 34 for farm schedule number. In almost all cases, anyone filling out a farm schedule was coded as farmer, whereas farm laborer was coded if a farm schedule had not been filled out. Persons living on farms who were returned as "Laborer--odd jobs," "Odd jobs," or "Working out," were given the code for farm laborer.

The index was designed to cover most occupational designations, but it was not exhaustive. When an occupational return was not found in the Alphabetic Index, or was not covered by it, the case was referred to the coding supervisor. In addition, the coders were instructed that when they encountered children under 18 years of age in certain occupations, they were to provide codes for alternative occupations, usually apprenticeships. Examples included the following: blacksmith, boilermaker, brickmason, cabinetmaker, carpenter, cooper, coppersmith, designer, draftsman, dressmaker (not in factory), electrician, machinist, mechanic, milliner, plumber, printer, stonemason, tailor, and tinner were coded blacksmith's apprentice, boilermaker's apprentice, etc.; cook and housekeeper were coded servant; dairy farmer and farmer were coded (dairy) farm laborer; and nurse was coded child' s nurse. There were also occupations for which children were not deemed to possess the necessary physical or mental requirements proprietary, official, supervisory, or professional pursuits. When children under 18 were returned in such occupations, the cases were referred to the oration chief. In some cases, the occupational codes that were provided differed from the schedule entries.2

There was also a list of "peculiar occupations for women." When a woman was returned as following such an occupation, the schedule was examined to determine whether an error had been made either in the occupation or in the sex of the person. This list included the following occupations:

Auctioneer Conductor
Baggageman Cooper
Blacksmith Craneman
Boatman Deck hand
Boilermaker Ditcher
Boiler washer Electrician
Bootblack Engineer (any)
Brakeman Engine hostler
Butcher Express messenger
Butler Fireman (any)
Cabinetmaker Flagman, railroad
Captain Foreman, lumber/camp
Foreman, mine/quarry Miner
Foreman (any construction industry) Molder (any metal)
Forester Motorman
Freight agent Pilot
Furnace man Plasterer
Garbage man or scavenger Plumber
Gas or steam fitter Pressman, printing
Heater Puddler
Hostler Railroad official
Inspector, mine/quarry Railway mail clerk
Ladler or pourer, metal Roofer
Laborer, coalyard Sailor
Laborer, pipeline Sawyer
Laborer, road or street Slater
Locomotive engineer Smelter man
Loom fixer Stevedore
Lumberman Stonecutter
Machinist Stonemason
Manager, mine/quarry Street cleaner
Marine Structural iron worker
Marshal Switchman, railroad
Master Teamster
Mate Tinsmith
Mechanic Toolmaker
Millwright Woodchopper

Persons on or assigned to public emergency work, i.e., WPA, NYA, CCC, or local relief work, were coded the same as other workers for their occupation entries. For their industry entries, such persons were also coded the same as workers in private employment when an industry was reported. When the return merely indicated the program, such as "WPA," the industry code was given as government. When a person reported two jobs, the first return was coded.

When the coders received portfolios for coding, they first checked the portfolio memorandum to see if the portfolio was to be examined for industrial home workers. An industrial home worker was defined as one who worked in his or her home for a commercial employer who furnished the materials or products on which the person worked. A proper return for an industrial home worker included the words "at home" following the occupational entry in column 28. The kind of business or factory by which the person was employed was entered in column 29. The coders were instructed to distinguish carefully between industrial home workers, who were working for commercial employers, and persons who worked in their own homes for themselves. Each person identified as an industrial home worker was recorded on a line on the "Industrial Home Worker Transcription Sheet" (Form P-358).

When the coding of a portfolio was complete, the coders made the proper entries on the portfolio memorandum and noted that the data for industrial home workers, if any, had been transcribed. The portfolios were returned to the control desk.

Verification of the occupation, industry, and class of worker coding was done by clerks in Operation 10. Not all of the coding was verified. Instead, sample verification was used. The proportion verified was determined by the section chief, based upon the experience and efficiency of the coding clerks. As coders became experienced, the amount of verification of their work was determined by the percentage of error in their previously verified work.

When portfolios were given to the verifiers, they went over several sheets and verified the accuracy of the occupation, industry, and class of worker symbols assigned by the coders. When an incorrect symbol was found, the verifiers changed it to the correct symbol and made an entry on a "Verification Slip" (Form P-355). This slip entry included the sheet and line of the E.D. on which the error was found and the occupation, industry, and, if involved, class of worker entries on the schedule, the symbol the coder assigned, and the corrected symbol. The clerks also verified any symbols entered in column J of the "Supplementary Questions" section of the schedule and checked to see that the transcription of symbols from column F to column U had been properly made.


  1. U.S. Department of Commerce, Bureau of the Census, Alphabetic Index of Occupations and Industries, prepared by Alba M. Edwards (Washington, D.C.: Government Printing Office, 1940).
  2. For discussion of this issue and, in particular, the issue of coding women in "unusual" occupations that is discussed below, see Margo Conk, "Accuracy, Efficiency, and Bias: The Interpretation of Women's Work in the U.S. Census Statistics of Occupations, 1890-1940," Historical Methods 14 (May 1981): 65-72.

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