President Trump on Thursday said he had instructed the Department of Commerce to "immediately begin work on a new and highly accurate" census that would exclude undocumented immigrants. But the census is a massive undertaking and has huge repercussions nationally,

The population survey helps decide how many congressional seats each state gets. Here's why a new one would matter.

The data collection that provides information on the country’s population has been the topic of discussion as President Donald Trump calls for a major change in its makeup. Trump said he wants undocumented people to be excluded from the count that makes up the U.S. Census.