(We've moved to: http://christinesleeter.org/racial-categories-in-the-census/)
Census categories are a clear example of the social construction of race. When sifting through the census to construct family trees and portraits of ancestors' neighbors, you will notice that people are always classified by race. You may be tempted to believe that means something fixed, decade after decade. In fact, however, racial categories reflected in the census are determined by law, applied by human judgment, and change over time.
The census is called for in the U.S. Constitution, particulars for each decade being established by Congressional legislation. Since the first census was taken in 1790, people have been enumerated and classified based on race and sex. Very interesting questions include: In any given decade, what categories existed? How were people categorized? And why were they classified?
Let's consider the first federal census, taken in 1790, and administered by federal marshals and their assistants. An Act of Congress specified how the census was to be administered, and wasn't revised until 1850. Between 1790 and 1850s, the available categories for people included: free white males sixteen and above, free white males under sixteen, free white females, all other free persons, and slaves. Indians "not taxed" were to be omitted. It was up to the census enumerator to decide which category people fell into, although birth dates were used to determine age. Why distinguish among free whites and free other?
Because racial classification determined rights. While free "other" on paper initially had the same rights as free whites, in practice they did not. As slavery became increasingly embedded, rights of free African Americans eroded. States began passing legislation barring free African Americans from rights such as voting, serving on juries, joining militias, and so forth. PBS offers an excellent teacher resource bank about race and rights that probes into what difference it made how one was classified.
Now consider the situation of a dark-skinned European immigrant coming into a setting in which people are classified by race, classification being largely a matter of physical appearance, and the rights to which you will have access depend on whether you are classified as "free white" or "free other." This appears to have been the situation one of my ancestors faced, whose passport description noted her dark complexion. One can speculate that a person in that situation would do everything possible to be viewed as white in order to enjoy rights of free whites.
Beginning in 1850, directions were revised every decade, including directions for reporting race. You can find directions for census enumerators on the U.S. Census website. There you will see shifts in how race was legally constructed.
For example, after the Civil War, since everyone was nominally free, the census did not need to distinguish between free and slave. People were still classified by race, however, and race was still very strongly related to rights. Consider the 1870 Census, which directed enumerators to fill in the age, sex, and color of each person, warning that "No return will be accepted when these spaces are left blank." In other words, an enumerator couldn't opt not to classify people. But unlike 1790-1850, there was no pre-determined list; enumerators could write down race or nationality as it seemed to present itself. So, people were classified as white, Negro, black, mulatto, Chinese, Japanese, Filipino, Mexican, and so forth. While Indians "not taxed" were still not counted, enumerators were directed to note Indians living off tribal lands with the designation "Ind."
But directions stressed the importance of making sure that people with any African ancestry were identified: "Be particularly careful in reporting the class Mulatto. The word is here generic, and includes quadroons, octoroons, and all persons having any perceptible trace of African blood. Important scientific results depend upon the correct determination of this class." (The directions did not elaborate on what scientific results they were referring to.) Again, since rights depended on racial classification, census enumerators were warned against allowing people with African blood, however little there might be, from passing as white.
With the dismantling of legalized racial segregation beginning in the 1950s, the link between racial classification and rights slowly began to erode, although that link still exists in practice. However, in the wake of racial desegregation, purposes and process for racial classification in the census has shifted. Data are now used to monitor racial disparities and progress (or lack thereof) toward closing them. In other words, rather than being a tool of enforcing racial segregation, census data now often serve as a tool for monitoring the contours of institutional racism. In addition, rather than people being classified by census enumerators based on physical appearance, people choose their own classifications, which are beginning to include the option of designating multiple ethnic backgrounds.