The information that the census gathers every decade is critical for the government and determines many factors, including funding for programs that benefit low-income families.
But it's not a perfect process. Officials usually plan for an inaccurate count, but the 2020 census may prove to be more difficult than usual.
Rob Santos with the Urban Institute, a nonprofit that's been researching the census, helps explain the obstacles.
On the potential addition of a question regarding citizenship:
"There is no question that in my mind that the citizenship question would deter participation by some parts of the public.
There is documented research by the Census Bureau itself as well as others that show people of immigrant backgrounds, non-citizens, Latinos, would be less likely to participate because of their fear and mistrust for how the data would be used."
On how a delay could affect the census:
"A delay would be absolutely disastrous. I don't believe there will be a delay. It would be the first time ever that a census has been delayed.
The problem here is that there is actually an act — the Census Act titled 13 — that mandates census day to be April 1st of each decade. So it would take an act of Congress to change that.
We shall see whether the the latest moves to alter that are successful or not. But I think that would be a high bar. I'm pretty confident that it's going to go on as scheduled."
On rethinking the way the census asks about race:
"The Census Bureau has been working on that for at least 20 years, if not more. The problem is that people think differently about race and ethnicity than the way that social scientists and demographers do.
Back in the day, a professor somewhere or a social scientist said, 'Oh, there is race and there is ethnicity, and the two shall never meet. They are different concepts and we need to measure them separately.' And the federal government's statistical agencies absorbed that and now are ruled by that through OMB (Office of Management and Budget).
But the fact of the matter is that people do not think that way. They cannot separate for cultural reasons or others; they don't want to separate the fact that they're Mexican American say versus white.
So for example, I'm a Mexican American. When I fill out the census form, I check the Latino-Hispanic-Mexican American box and when it comes to race I mark 'other' an insert 'mestizo' because that's how I feel about race and ethnicity."
On making the census more accurate:
"It's all going to boil down to people participating at a higher rate.
The accuracy of the census is going to be determined by the extent to which duplicates and imputations and other types of erroneous inclusions in the census count outweigh or shake out against the collection, the millions, possibly tens of millions of people who don't participate if we don't do anything now."