“For every single illegal immigrant family in this country, it costs $20,000 — it costs us $20,000; $20,000 in infrastructural costs. They pay about $10,000…

During an Oct. 9, 2007, debate, Tom Tancredo pressed to change immigration policy by making a dollars and cents argument. Tancredo said an average household with an undocumented worker costs the country more than it pays in taxes.

PolitiFact found nothing to disprove Tancredo’s statistics, but no one who could verify them — including his campaign.

Asked where the statistics originated, Tancredo spokesman Alan Moore referred to the Center for Immigration Studies. Bryan Griffith, a center spokesman, said officials there know of no CIS report with those numbers.

However, Griffith pointed to a 2004 report that showed families with undocumented immigrants contributed $4,200 on average to the federal government, but cost Uncle Sam $6,950.

That’s a long way from the $20,000 in costs and $10,000 in taxes line that Tancredo used. Pressed for more specifics, Tancredo’s campaign at first asked for details on the very study it was citing. Weeks later, spokesman Moore pointed to another report.

In a 2007 study, Robert Rector of the Heritage Foundation, a conservative think tank in Washington, found that families with low-skilled immigrants cost taxpayers about $30,130 in 2004. Those households paid about $10,573 in taxes for 2004.

But that study includes all low-skilled, immigrant households in America, representing 15.9-million people. About 60 percent were entirely legal households, and 40 percent had undocumented workers. Tancredo’s statement is about undocumented workers only, so this study is off point.

We found no other recent studies on the overall costs and benefits linked to families of undocumented workers. Moreover, critics point to flaws in the studies showing larger costs than contributions by undocumented workers.

Tim Vettel of the American Immigration Law Foundation said he was uncertain where Tancredo’s statistics originated but lumped them with other reports that the foundation, which promotes immigration, has criticized.

Focusing more broadly on all immigration, the American Immigration Law Foundation said in November 2007 that most studies rely on one-year “snapshots” of the immigrant population without taking into account rising income and future tax contributions. The foundation also said the studies fail to count economic contributions such as consumer purchasing power.

The Congressional Research Service reached the same conclusion after reviewing studies in 2005.

Its report said information that typically is the basis for cost estimates is not collected, producing estimates based on assumptions and disagreement about accuracy. In the case of illegal immigration, analysts tend to disagree on how many government benefits undocumented workers actually use.

“It is very difficult to enumerate a population which is trying to avoid detection by the government,” analyst Alison Siskin wrote.

Given the lack of information, and dispute over reports we did find, we rule Tancredo’s statement Barely True.

Editor’s note: This statement was rated Barely True when it was published. On July 27, 2011, we changed the name for the rating to Mostly False.