Still, to address the country’s changing demographic landscape, the Census Bureau frequently conducts tests in between decennial censuses. In August 2015, the bureau sent a questionnaire dubbed the National Content Test to 1.2 million households. It had two objectives, according to John Thompson, the director of the U.S. Census Bureau, “to evaluate and compare different versions of questions to ask in the 2020 census, such as those about race and origin,” and to encourage households to respond to the census online, the cheapest and most efficient option.

The questionnaire emulated another experiment also aimed at eliciting detailed race and ethnic reporting known as the Race and Hispanic Origin Alternative Questionnaire Experiment. It involved half a million households and was conducted close on the heels of the 2010 census. The results showed that the bureau would be better off scrapping the separate “Hispanic” ethnicity question on the census form and putting it alongside the list of categories asking for a person’s race. In doing so, the census results were more reliable—and valuable—since a larger share of people reported their race. In fact, in the experiment sample, “Some Other Race” declined from 7 percent of the population to less than 1 percent. But focus-group participants who ran alongside the AQE raised a series of questions: What was the census form really asking? Some felt “race” and “origin” were the same. Others believed “race” was defined as skin color, ancestry, or culture, while “origin” referred to where they or their parents were born. The takeaway: The terms were confusing and needed to be defined or eliminated altogether.

The bureau’s focus-group moderators went a step further, asking questions to try to understand participants’ “situational identity,” too, recognizing that respondents discussed and reported on their race differently depending on the context in which questions were asked. They explored themes of awareness and fluidity with questions such as, “When did you first become aware of your race?” to understand if and how racial identity changed over time. Jones noted that “the categories are not an attempt to define race biologically, anthropologically, or genetically, but we know that some people interpret it that way.”

Census officials also found that people were more likely to report their race as long as they had a way to express their self-identification. “If you look at the current way we ask the race and ethnicity questions, one of the issues you will see here is that we don’t have a write-in line for ‘White’ or ‘Black,’ so many groups went down to the ‘Some Other Race’ category,” Jones told me. When space was offered for people to write in their choices, respondents seldom checked the box that said “White” or “Black” and instead wrote in “Irish” or “Jamaican” or similar. “The proportions were very different, too. It went from 3 to 5 percent of the white or black population giving the bureau detailed responses, to over 50 percent of whites and 75 percent of blacks using the write-in lines,” he said.