Immigration: What Are the Real Numbers? How many illegal immigrants are in the United States? How many arrive each year? Where do we get these numbers and how reliable are they?
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Immigration: What Are the Real Numbers?

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Immigration: What Are the Real Numbers?

Immigration: What Are the Real Numbers?

Immigration: What Are the Real Numbers?

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

How many illegal immigrants are in the United States? How many arrive each year? Where do we get these numbers and how reliable are they?


Mention the subject of immigration and you're likely to start a debate about security, the workforce, social services and politics. But the debate is often based on emotion or anecdotes. So we set out to learn what is really known, the hard facts.

NPR's Ted Robbins begins a series of reports with a look into the biggest number of all, just how many illegal immigrants are actually in the United States.

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 Passel.

Mr. JEFF PASSEL (Pew Hispanic Center): Until quite recently there was nobody really charged with doing this in the government.

ROBBINS: Passel 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 Passel says there is a growing consensus.

Mr. PASSEL: 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. DONALD BARLETT (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 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 microtrends.

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 then all of a sudden, these schools, which 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 five percent, but not 100 percent. And he says as more data is gathered, the estimates will become more accurate.

Ted Robbins, NPR News.

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Getting a Handle on 'Fuzzy' Immigration Numbers

Efforts to estimate the number of illegal immigrants living in the United States can be tricky. To begin with, any estimate is obviously a snapshot in time. The current estimated range is between 8 million and 20 million people, though almost all reputable sources believe the 8 million mark was surpassed several years ago. The number most commonly cited is between 11 million and 12 million.

That estimate is derived by using what's called the statistical "residual method. Here's how it works:

1 — Take the number of legal immigrants: about 24-25 million. They are relatively easy to track because they have documents such as green cards.

2 — Take the total number of foreign-born persons in the United States: about 35-36-million. That number includes legal immigrants, but it also accounts for other immigrants, as statistically sampled in periodic U.S. Census Bureau surveys (those are interviews done to update the 10-year Census).

3 — Subtract the legal immigrants from the total number of foreign-born immigrants. Illegal immigrants equal roughly 11 million to 12 million.

Demographer Jeff Passell at the Pew Hispanic Center says illegal immigrants are surprisingly forthcoming when interviewed anonymously. Plus, the surveys use statistically valid sampling methods.

An Accurate Picture?

Other sources, such as investigative journalist Donald Barlett, believe the number is an underestimate, because illegal immigrants are wary of authorities and tough to track down.

Barlett cites a report by the investment firm Bear Stearns that estimates as many as 20 million illegal immigrants as of last fall. That report uses micro-economic trends such as housing starts, school population forecasts, and soaring remittances—the amount of money sent back specifically to Mexico.

What Border Patrol Apprehensions Tell Us

The federal government cites the number of Border Patrol apprehensions to gauge the success of current border-enforcement strategy. Here's how the numbers are derived:

When illegal immigrants are caught, they are taken to a processing center, where they are photographed and fingerprinted. Those with criminal records and those who admit they are not from Mexico are detained. The "OTMs" (other than Mexicans) are detained until the can be returned, usually via airplane, to their home country.

Many illegal immigrants are released on their own recognizance, pending a court date. They often disappear into cities. However, the overwhelming majority of those apprehended are Mexican; they are put on a bus and driven to a port of entry on the Mexican border and released to walk a few feet back into Mexico.

Since many of these illegal immigrants come from the deep interior of Mexico, once they are dropped off at the border, they will often try again to enter the United States without authorization. (Some are flown back to Mexico City, but that's a voluntary program.) Immigrants I've interviewed often tell me they had to try two, three, four times or more to enter the U.S. — and eventually they made it in.

Double Counting?

The problem is, each time an illegal immigrant is caught, the Border Patrol counts that person as an apprehension. Same person, three apprehensions — sometimes on the same day. Even the Border Patrol says three people enter the United States illegally for every one person who is caught trying to do so.

Critics such as Douglas Massey, a Princeton University sociologist and expert on Mexican migration, say the apprehension figure is misleading.

"There is virtually nothing one can infer about the volume of illegal migration from the number of apprehensions," Massey told the Arizona Daily Star.

Because those apprehended are photographed and fingerprinted, it seems likely the federal government has statistics — or could compile them — on the number of distinct individuals it catches. But the government has not released those figures for several years. Meanwhile, a number of media outlets continue to use "apprehensions" as interchangeable with "permanently removed."

Immigration vs. Migration

Historically, people have migrated from Mexico illegally for seasonal work, especially in agriculture. No agency tracks those who migrate illegally, but they are not "immigrants" because they do not stay in the United States. Instead, these migrants moved back and forth across the border.

But border security has increased both the risks and the cost of that circular migration. As a result, there is anecdotal evidence that more people are staying in the United States illegally and even sending for their families. But, again, no numbers yet exist that would accurately prove or disprove that theory.