• Making online forms work. Using the Internet will require layers of security against fraud and mistakes — such as a husband and wife filing duplicate Census forms for their household. It also would require an extensive publicity campaign to alert and reassure people about the change.
Countries such as Canada typically require Internet Census respondents to enter a unique ID number contained in a letter delivered to their homes. In the USA, that wouldn't work for millions of homes that get mail delivered to a post office box or that don't get mail. The Census Bureau might be able to reach some by phone.
All that would likely still leave millions of doors for Census takers to knock on, but savings from using online forms still could be enormous.
• Privacy concerns. The USA has resisted a national registration system for its residents, a way of life in many other countries.
Scandinavian countries, Holland and Germany have systems that create a complete administrative record for every resident.
"They don't have to go out and count the entire population every five or 10 years," says Kenneth Prewitt, Census Bureau director in 2000. "The sophisticated systems in Europe require you to report change of address. In Holland, it records when you go to school, when you leave your job."
Americans must decide if they want a national file on every resident to make government more efficient or "do they worry about government accumulating big data bases on people?" Groves says. "In Scandinavian countries, they're quite happy, and stopped doing censuses."
While the 2010 Census continues, a different Census in 2020 is taking shape — a move many Americans say is overdue.
"Pretty old-fashioned," Roger Tschappatt, a retired elementary school teacher in Wheeling, W.Va., called the current methods. "We have great statisticians in this country. They could do it very cheaply and accurately through random sampling."
The Census proposed using statistical sampling in 2000 — a method that involves counting a segment of the population and extrapolating the data for the entire population from that sample. The House of Representatives, controlled by Republicans at the time, challenged the method as unconstitutional. Democrats largely supported sampling because it would count people — mostly minorities — disproportionately missed by traditional methods.
The Supreme Court ruled in 1999 that statistical sampling could not be used to calculate the population for purposes of determining how many House seats each state gets. Sampling numbers still can be used to help allocate more than $400 billion a year in federal money.
Sampling or no sampling, the Census should be done electronically, said Frederick Rone, 24, an electrical engineer for the Tennessee Valley Authority in Knoxville. "Most people have an e-mail or cellphone text or something," Rone said. "I don't really know anyone who doesn't."
Coburn advocates a fast move to the Internet, which he says would cut costs in half. "If they do 70 percent of it online, you have all the resources left" to chase the 30 percent who don't respond, he says.
There is congressional pressure to lock in a plan that will set a design and a budget for the 2020 Census as early as possible, Groves said.
"I reject that argument," he said, pointing to technological developments that are unforeseen today. "We need to be nimble in a way we haven't had to be in the past."