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Woman using a Hollerith pantographic card-punching machine
Woman using a Hollerith pantographic card-punching machine, Harris & Ewing.

How the U.S. Census Drove Computing Technology

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This post was written by Lynn Weinstein, Business Reference Librarian in the Science, Technology, and Business Division.

I recently received my 2020 Census questionnaire in the mail and put it aside. In response to the initial spread of covid-19 many localities have begun social distancing and sheltering in place. Stuck at home with no clear end to the pandemic in sight, it seemed like I had endless time on my hands. I did finally open my Census questionnaire and filled it out online in a matter of minutes. Census responses are important, because they can impact the drawing of congressional districts, the federal funding of programs, and they provide crucial statistics related to industries.  The proper allocation of resources based on Census data is particularly important in our current national health emergency, when accurate numbers direct the allocation of lifesaving resources.

Herman Hollerith
Herman Hollerith, 1884.

The early Census counts were tabulated by hand. In 1889, there was a competition for the 1890 Census contract. Herman Hollerith (1860-1929), a Census Special Agent (1879-1882) and inventor, won the competition using 100 machines operated by 80 clerks processing and competing against two hand counting systems. Hollerith, widely regarded as the father of modern automatic computation, based his tabulating system on punch cards inspired by observing a train conductor track passenger traits, such as hair and eye color, on railroad tickets using distinct punch patterns.

The Hollerith Electric Tabulating System was used for the 1890 and 1900 Census, allowing for large scale data processing. Holes were punched on small cards in a variety of patterns by an operator, with each hole representing a different response. The machines were run through a computer sorter and then were counted by a machine that tracked the results in each category, so you could combine results and find out, for instance, how many people of a certain ethnicity or vocation were located in a particular geographic area. These systems were also used for accounting and inventory work and are even the basis for U.S. state voting systems that still use punch cards. Hollerith’s punch cards, based on the Jacquard loom, were the size of the 1889 dollar bill, and set the industry standard for storing and processing information for the next century. Hollerith’s Electric Sorting and Tabulating Machines were used in conducting the census for a number of countries and were used by the early U.S. railroad and food processing industries.

Initially, Hollerith did business under his own name, The Hollerith Electric Tabulating System, specializing in punched card data processing equipment described in his U.S. patent as the “Art of Compiling Statistics.” In 1896 he incorporated as the Tabulating Machine Company, focusing on developing large tabulating systems customized for a particular organization.  It was subsequently purchased in 1911 by Charles R. Flint as part of the holding company Computing=Tabulating=Recording Company, which was renamed International Business Machines (IBM) in 1924.

As we set out this year to complete the first online Census, it is interesting to reflect on the origins of tabulating machinery – the forerunner of computers and the Internet. It is crucial that everyone participates in the online 2020 Census and be counted. It ensures each community has appropriate representation, and in times of national emergency, it also means local communities, hospitals, schools, and industries have what they need.

two women the one on the left crouching holding a paper that has rolled from a machine while the one on the right is standing looking down at the machine
New machine to speed up statistics of Census of 1940. On the left is Operator Ann Oliver with Virginia Balinger, Assistant Supervisor of the current Inquiry Section on the right, December 2, 1939. Harris & Ewing.

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Primary Sources

Sources for Teachers 


Internet Sources

  • Search “Census” on for legislation, communications, committees, and more.
  • The Census Bureau is the federal government’s largest statistical agency, dedicated to providing current facts and figures about America’s people, places, and economy.

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