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Exploring Census-Taking Processes Through the Years with Primary Sources

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This post is written by Michael Apfeldorf of the Library of Congress.

Take a moment to observe this early 20th century photograph depicting a room full of women working. Speculate about what the women are doing. What questions do you have about the photograph?

What do you think is happening in this photograph? Think for a  moment and then click through to read the item record for more information.

If the 2020 U.S. Census is on your mind, you might have deduced that they are busy compiling census data. Try this opening primary source analysis with your students. As you discuss their theories about what the women are doing, pull out and highlight any aspects of their speculations that touch on tabulation, computation, or other large-scale data processing.

Now in 2020, over 100 years after this photograph was taken, the United States is once again preparing to undertake its decennial census, mandated by the U.S. Constitution for the purpose of determining how many seats in Congress go to each state. As such, it’s a good time to explore  Library of Congress primary sources to see how the census has changed over time.

One change that students will no doubt bring up is that data tabulation appears to have been significantly more labor intensive one hundred years ago, as compared to today, when we have computers to help us process data. A close examination of additional primary sources can deepen this exploration of technology and process innovations that have occurred through the years as we have sought to make the census a more efficient undertaking.

For instance, show students two additional photographs illustrating census workers from this time period. Withhold the photograph captions from students initially and allow time for careful observation and study. What do they notice about the technological innovations shown? How do they think the machines worked?

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

Sorting machine (Census)

How did punch-card technology, first developed in 1890, make the processing of data faster than previously? For more information, students can also visit this related newspaper pictorial report from the 1920 Evening Star.

Census Advertisement from the April 2, 1960 Jackson Advocate

Next, jump ahead forty years and show students this newspaper advertisement from 1960, when the U.S. government first began mailing out census forms to homes.  Once more, see if students can identify innovations shown in the source.  Students may note that the advertisement urges families to fill out the forms in advance for visiting enumerators.  Additionally, residents are informed that only one out of four homes will be randomly selected to answer certain questions. What might be the goal of these process innovations?

Invite students to explore the Library’s collections further to discover more about the history of census taking, or ask them to examine historical statistical atlases to reflect on how the data was compiled and presented to the American public.  Let us know what interesting insights your students come up with!

Also, you can educate your students about their civic responsibility in the upcoming 2020 Census and the history behind it all with the U.S. Census Bureau’s Statistics in Schools program. New activities designed specifically for Constitution Day spotlight the history of the census and the importance of making sure everyone is counted, especially children during the 2020 Census. Explore the site for free classroom-ready activities at

Comments (2)


  2. Much respect to the Tuskegee Airmen!

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