What is this "census" everyone is talking about?

The US Constitution (Article I, Section 2) mandates that a census be conducted every 10 years to count the population in all states. The data collected determines how many seats each state will have in the U.S. House of Representatives, and will be used to determine the boundaries of legislative districts. In addition, census data are used to make decisions about scores of federal programs -- everything from school lunches to highways to health clinics.

Who has to complete the census?

Everyone is required by law to complete the census. If a household does not self-respond, the Census Bureau will visit in-person to ensure a 100% response rate.

Everyone should be counted where they live and sleep most of the time. This means college students living away from their parents complete the census themselves. Parents should not count any of their college students unless those students live with them while in school.