ED GORDON, host:
As the debate over illegal immigration continues, one of the biggest questions that's being raised is, just how many undocumented people are in the United States?
NPR reporter Ted Robbins says the answer to that question, varies.
TED ROBBINS reporting:
You might think the federal government has a clear handle on the number of illegal immigrants living in the U.S. Well not according to Jeff Passell.
Mr. JEFFREY PASSELL (Demographer, Pew Hispanic Center): Until quite recently, there was nobody really charged with doing this, in the government.
ROBBINS: Passell was a demographer with the U.S. Census Bureau. He's now with the Pew Hispanic Center.
He points out that the Federal Office of Immigration Statistics only began gathering data, seriously, when the Department of Homeland Security was established in 2003. Today, estimates on the number of illegal immigrants in the country, vary from eight million to 20 million. That's a pretty wide range, especially when the country is grappling with implementing solutions; from legalization to deportation.
But Passell says there is a growing consensus.
Mr. PASSELL: You have a number of quite restrictionist groups, and a number of open borders groups, as well as a number of immigrant rights groups--who are all using numbers that are within one or two million of each other.
ROBBINS: That's Passell's number: 11 to 12 million. How'd he get it? By taking the number of foreign-born living in the U.S. legally--about 24 to 25 million who have government-issued documents--and comparing them with the total number of immigrants based on census surveys. That's about 35 to 36 million. Subtract the total immigrants from the legal immigrants, and you get 11 to 12 million.
But Don Barlett doesn't agree with that figure.
Mr. DON BARLETT (Pulitzer Prize winning reporter/author): Part of the problem, of course, is you're counting people who don't want to be counted.
ROBBINS: Don Barlett is half of the Pulitzer Prize winning reporting team, Barlett and Steele. They did a story for Time Magazine in 2004 called: Who Left the Door Open? Here's how they got their number.
They started with Border Patrol estimates that say for every apprehension on the border, three people get through. That's three million a year. Multiplied out, Barlett and Steele got a 15 million, total. And by now, Don Barlett thinks even that's low.
Mr. BARLETT: And about the only thing that a reader or listener can, you know, put in the bank, is that any number he or she hears, sees, or reads, is probably understated--in some cases exponentially.
ROBBINS: Barlett cites a report done last year by the investment firm, Bear Stearns, estimating as many as 20 million illegal immigrants in the country. That report extrapolated a total by looking at several micro trends.
Mr. BARLETT: They went out and looked at school districts, certain school districts around the country. Looked at their past student projections, saw how those turned out. Looked at their current projections, and all of a sudden these schools that weren't supposed to have a need for any new buildings, now are building new buildings. And the reason, of course, is the illegal immigrant issue.
ROBBINS: The Bear Stearns report also drew conclusions from skyrocketing remittances: the amount of money sent back to Mexico by immigrants in recent years.
Jeff Passell says his figure, based on census numbers, could be off by as much as 5 percent, but not 100 percent. And he says, as more data is gathered, the estimates will become more accurate.
Ted Robbins, NPR News. Transcript provided by NPR, Copyright NPR.