How We Unduplicated Responses in the 2020 Census

By Andrew Keller, Mathematical Statistician, Decennial Statistical Studies Division; and Ryan King, Mathematical Statistician, Decennial Statistical Studies Division

At the U.S. Census Bureau, we often say our goal is to count everyone once, only once, and in the right place. Sometimes in an effort to count everyone in a census, we end up counting some people more than once. The Census Bureau refers to a person counted more than once as a “duplicate.”

Today, we’ll talk through situations where that can happen and how we resolve duplicates in the 2020 Census.

Reasons for Duplication

There are several reasons for duplicates in a census:

We receive more than one response for an address.
People are counted in more than one place because of potentially complex living situations.
There might be an issue with the address — a housing unit is on our address list more than once or census materials are misdelivered.

We use a special algorithm to resolve the first situation and a series of steps to resolve the second and third. Continue reading...