The U.S. Census Bureau says improvements to the design of the 2020 census questions and the tabulating of answers led to an increase in the count of multiracial people in the United States, defending its method against arguments that the jump was mostly a statistical illusion.

The United States’ largest statistical agency said in a statement this week to The Associated Press that millions more people reported multiple responses to the race question in 2020 than they did in 2010.

The Census Bureau’s statement was made in response to a paper published last month by two Princeton University sociologists that argued that the 276% increase from 2010 to 2020 in people classified as multiracial was largely due to a change in how people were classified by census officials rather than strong shifts in racial or ethnic identity or major growth. The Census Bureau for the first time provided space on the census form for people to write in their families’ origins, which guided how the statistical agency categorized them by race.

— The Associated Press