There is currently a legal battle over changing the US census to include a citizenship question.
The plaintiffs argued that participation in the census will be depressed by the addition of the new question, causing a significant undercount. If the government is successful in adding the citizenship question, the census will yield flawed data.
- A C.E.O.’s Plea: Don’t Mess With the Census - NYT Op-ed
The claim certainly makes logical sense, because we expect illegal immigrants to tend to avoid revealing their citizenship status. However, the citizenship question has been on the census before, so we can compare data from those periods to data from other periods where the citizenship question was not on the census. In that comparison we can find disparities that may be explained through lack of participation, as the claim alleges.
So regardless of the logic in the claim, is it true that a citizenship question affects participation in the US census?
An already existing question provides some helpful background information, but not an exact answer to this question.