A New Study from Yale University Indicates there are 22.8 Million Undocumented Immigrants Living in the US

A new study authored by Yale University’s Dr. Mohammad Fazel Zarandi estimates that there are 22.8 million illegal immigrants in the United States. This is over double estimates compiled by the Department of Homeland Security, which claims 11.1 million illegal aliens live in America.

The paper’s abstract summarizes why Dr. Zarandi’s estimate is both higher and more accurate than the government’s own statistics:

We apply standard operational principles of inflows and outflows to estimate the number of undocumented immigrants in the United States, using the best available data, including some that has only recently become available. We generate a lower bound for the number of undocumented immigrants using conservative parameter values that underestimate inflows and overestimate outflows.

Our lower bound is close to 17 million, 50% higher than the most prominent current estimate of 11.3 million, which is based on survey data and thus different sources and methods. Standard parameter values generate an estimate of 22.8 million undocumented immigrants, twice as large as the current estimate.

Conservatives have argued for well over a decade that the number of illegal immigrants is widely underestimated by both the government and think-tanks which base their calculations on government data. Finally academics are starting to take an independent look at the problem.

But the fact that the paper needed to be written at all highlights an insidious problem: we really don’t know how many illegal immigrants live in America. With that in mind, I think it’s worth surveying the research on the topic—at the very least I’ll be able to give you some context for the broader debate.







How Many Illegal Immigrants Live in America?

Yale’s new study, while significantly higher than government estimates, is actually a middle-of-the-road estimate.

On the low end, Pew Research estimates that the number of illegal immigrants living in the US is roughly 11.1 million—this number tracks fairly closely with official government figures, which isn’t shocking because Pew’s data is largely drawn from government sources.

But there are two big problems with this figure.

First, the data doesn’t include anchor babies (the children of illegal immigrants who were born in the US, for the sake of subverting America’s deportation laws). There are at least 6.5 million anchor babies in America, and they should rightly be included in the number of illegals.

Of course, there’s a big debate over whether or not being born on the land should grant citizenship—I won’t get into the meat of it. But you should know that only 33 of the world’s 196 countries grant citizenship jus soli (Latin for “by right of the soil”). Citizenship by birth on the land isn’t the only (or necessarily best) way to grant citizenship.

Second, the number of illegal aliens itself may be underestimated due to political pressure—too many illegal immigrants make the government look bad. It makes them look like they don’t have control of the situation.

This could explain why the number of estimated illegal immigrants peaked in 2007, and subsequently remained stagnant—despite the fact that illegal immigration maintained a linear rate of growth between 1990 and 2007. It’s possible this was caused by 2008’s recession, but then why no similar drop following the Dot-Com Bubble?

Furthermore, we know for a fact that the reason deportations increased after 2007 is that the Obama Administration simply changed the definition of “deportation” to inflate the numbers. Political optics matter.

Now for the high end: it’s thought there are up to 30 million illegal immigrants in the US.

This number has been best explained by conservative author Ann Coulter in her book Adios America. She based her findings off banking and remittance payment records, government service demands (like how many immigrants were applying for drivers’ licenses), and arrests by the U.S. Department of Immigration and Customs Enforcement (DHS).

There was a time when Coulter was ridiculed for her “baseless” claims—in light of Yale’s recent study, they don’t look so unreasonable.

In any event, the Yale study should force everyone to reflect on the accuracy of the DHS’s figures.