In Counting Illegal Immigrants, Certain Assumptions Apply

How many people in the U.S. can be considered illegal immigrants?

A range of estimates, including one by the U.S. government, put the number at between 10.8 million and 11.9 million. {snip}

{snip}

Of the many studies that have attempted to calculate the size of the illegal-immigrant population, the most widely cited are from three sources: the Department of Homeland Security; the Center for Immigration Studies {snip}; and the nonpartisan Pew Hispanic Center. The government and CIS both put the number at 10.8 million in 2009, while Pew counted 11.9 million in 2008.

{snip}

Researchers at CIS and Pew and in the federal government use a decades-old technique that looks at the number of foreign-born people in the U.S., as counted by annual census surveys. Then they subtract the number of foreign-born people in the U.S. legally, based on immigration records and projections of deaths and outmigration. The remainder is believed to be the number of illegal immigrants.

{snip}

These studies presume that about 10% of illegal immigrants aren’t counted by census takers. But that figure largely is based on a 2001 University of California-funded survey of 829 people born in Mexico and living in Los Angeles, in which individuals were asked, among other things, whether they responded to census interviewers a year earlier. Representatives of nearly two in five households refused to answer that survey, and those who didn’t might have been more likely to skip the census count as well.

{snip}

{snip} In 2005, Robert Justich, then a portfolio manager for Bear Stearns, co-wrote a report putting the population at as high as 20 million, citing increases in remittances to Mexico and in housing permits in communities with enclaves of illegal immigrants.

{snip} “The assumption that illegal people will fill out a census form is the most ridiculous concept I have ever heard of,” says Mr. Justich, who now owns a music and film production firm in Hoboken, N.J.

Other researchers criticize the Bear Stearns analysis for failing to note that the surge in remittances might simply reflect better record-keeping. Nor would a rise in remittances necessarily mean a surge in illegal immigration. {snip}

{snip}

Though the Census Bureau’s studies are the basis for most of these counts, the agency itself doesn’t seek to identify individuals’ immigration status. Robert M. Groves, director of the Census Bureau, cites two major reasons. First, asking people about their citizenship might drive down the overall response rates to the census.

Second, the Census Bureau doesn’t have the funds to conduct a massive effort to count illegal immigrants.

{snip}