The number of undocumented immigrants in the United States appears to be far higher than the 6-million the government has estimated, a growing number of federal officials and other experts say.
The discrepancy has surfaced in recent weeks as the results of the 2000 Census have been released. And while researchers don't agree on how many undocumented immigrants live in this country, a growing consensus says the number could be at least 50 percent higher than the official estimate _ 9-million or higher.
The presence of millions of people in this country previously unknown to the government has important policy implications, from border enforcement programs to visa regulations. It also could explain why unemployment rates and wage trends have seemed out of step with the tight labor market of recent years.
Officials and researchers point to the census as evidence in arguing that the 6-million figure is far too low. The Census Bureau had estimated _ based on birth, death and other records _ that its 2000 head count would find 275-million U.S. residents. The number that came in was much higher: 281.4-million. Then, a survey conducted after the census as a quality check arrived at an even higher number: 285-million.
The census also found 35.3-million Hispanics, a number much higher than the 32.5-million the government had estimated.
The most likely explanation for the gaps between those numbers is that the nation's foreign-born population is much larger than previously believed, say Commerce Department and Census Bureau officials, as well as a number of outside researchers.
"Immigration _ unmeasured immigration _ is the thing we are looking at," said John F. Long, chief of the bureau's population division. "The biggest candidate is . . . undocumented" immigrants.
Officials hope to resolve the discrepancy by fall, because it is part of a larger decision on whether federal money should be distributed based on the census head count or a figure adjusted to compensate for millions missed in the census.