U.S. population estimated at 306 million to 313 million

By Carol Morello
Washington Post Staff Writer
Monday, December 6, 2010; 7:38 PM

The population of the United States is 306 million. Or 313 million. Or somewhere in between.

If those statistics sounds more vague than those usually announced by the Census Bureau, it's largely because demographers don't agree on how to count immigrants. The range of 7 million people between the estimates is less precise but more honest, Census Director Robert M. Groves said Monday in presenting the numbers to demographers meeting at George Washington University.

The official population count from this year's census, expected to be closer to 308 million, will come at the end of this month and will be the basis for reapportionment of seats to the House of Representatives.

Census statistics are often more approximate than is suggested by precise numbers. The population clock on the Census Bureau's Web site April 1, which was Census Day, was 308,977,944. On Monday at 3 p.m., it stood at 310,859,593.

The official count in 2000 was 281 million.

The varying estimates announced Monday reflect a quality-control check on the decennial census. They were produced by a team of Census Bureau demographers who were incommunicado with those working on this year's numbers. The estimates team checked birth and death records and calculated how many new immigrants were in the country on Census Day this year.

One key source came from questions on the American Community Survey that asked people whether they were living at the same address a year ago and in what year they came to the United States.

After conferring with demographers from universities across the country, census officials realized that many demographers disagree on how much emphasis to put on each answer.

"Some experts say one question was a superior source, and others say the other is a superior source," said Mary Anderson, a University of Michigan sociologist. "It's a good thing [the Census Bureau is] using expert opinion and making variations of estimates."

Ultimately, the Census Bureau came up with five variations of population estimates, each reflecting an analysis that Groves characterized as "plausible."

The different ways to count immigrants were responsible for 5 million of the 7 million people between the estimates, census officials said. There was also a range of estimates about the percentage of people younger than 20 who are Hispanic. Census figures show they are at least one in five youths and as many as one in four.

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