Counting 11 million undocumented immigrants is easier than you think

A screenshot of The Conversation article published online.

A screenshot of the original article published on

Jennifer Van Hook, Pennsylvania State University

News organizations widely report that there are 11 million unauthorized immigrants living in the United States. But where does this figure come from?

Donald Trump has falsely asserted: “It could be three million. It could be 30 million. They have no idea what the number is.”

Jennifer Van Hook

Jennifer Van Hook

In the third debate, Hillary Clinton said, “We have 11 million undocumented people. They [undocumented parents] have 4 million American citizen children. 15 million people.”

The confusion is warranted. After all, the U.S. Census Bureau does not ask people about their immigration status, so how can we know much about the unauthorized foreign-born population?

Well, demographers have figured out a simple and effective way to estimate the number of unauthorized immigrants. In the last five years, my colleagues Frank D. Bean, James D. Bachmeier and I have conducted a series of studies that evaluate this method and its assumptions. Our research on the methods used to estimate the size of this group indicates that these estimates are reasonably accurate.

Here’s how it works.

A simple formula

Beginning in the late 1970s, a group of demographers consisting primarily of Jeffrey Passel, Robert Warren, Jacob Siegel, Gregory Robinson and Karen Woodrow introduced the “residual method” for estimating the number of unauthorized immigrants living in the country. At the time, Passel and his collaborators were affiliated with the U.S. Bureau of the Census and Warren with the Office of Immigration Statistics of the Immigration and Naturalization Service. Much of this work was published in the form of internal reports, but some of it appeared in major journals.

The residual method uses an estimate of the total foreign-born population in the country (F), based on U.S. Census data. Researchers then subtract from it the number of legal immigrants residing here (L), estimated from government records of legal immigrants who receive “green cards” minus the number that died or left the country. The result is an estimate of the unauthorized population (U):

F – L = U

Various adjustments are typically made to this formula. Most adjustments are minor, but a particularly important one adjusts for what researchers call “coverage error” among the unauthorized foreign-born. Coverage error occurs when the census data underestimate the size of a group. This can occur when people live in nonresidential or unconventional locations – such as on the streets or in a neighbor’s basement – or when they fail to respond to the census. Coverage error could be particularly high among unauthorized immigrants because they may be trying to avoid detection.

Currently, the Department of Homeland Security and the Pew Hispanic Center are the two major producers of estimates of the unauthorized foreign-born population. This report, compiled by Passel, who now works at Pew, summarizes many of the estimates. It shows that the estimated number increased steadily from 3.5 million in 1990 to 12.2 million in 2007, but declined between 2007 and 2009 and has since stabilized at around 11 million.

How accurate are the estimates?

The residual method has been widely used and accepted since the late 1970s. Within a reasonable margin of error, it predicted the number of unauthorized immigrants to legalize under the Immigration Reform and Control Act of 1986, which, among other things, granted permanent residency status to unauthorized immigrants who had been living in the country since 1982. The residual method predicted that about 2.2 million met the residency requirement and the actual number to come forward was about 1.7 million.

Both Department of Homeland Security and Pew have used the residual method to produce estimates of the unauthorized population since 2005. Despite using slightly different data and assumptions, Pew’s and the Department of Homeland Security’s estimates have never differed by more than 600,000 people, or 5.5 percent of the total unauthorized population.

Nevertheless, many skeptics question a key assumption of the residual method, which is that unauthorized immigrants participate in census surveys. Both Pew and the Department of Homeland Security inflate their estimates to account for the possibility that some unauthorized immigrants are missing from census data. Pew inflates by 13 percent and the Department of Homeland Security by 10 percent. But is this enough?

My colleagues and I estimated coverage error among Mexican immigrants, a group that composes 60 percent of all unauthorized immigrants. Even if they are not counted in a census, populations leave “fingerprints” of their presence in the form of deaths and births. Because people give birth and die with known regularity regardless of their legal status, we were able to use birth and death records of all Mexican-born persons to determine the number of the Mexican-born persons living in the U.S. We also looked at changes in Mexican census data between 1990 and 2010 to gauge the size of Mexico’s “missing” population, most of whom moved to the United States.

We then compared these estimates based on births, deaths and migration with the number of estimated Mexican immigrants in census data.

Based on this analysis, we found that the census missed as many as 26 percent of unauthorized immigrants in the early 2000s. We speculated that this could have been due to the large numbers of temporary Mexican labor migrants who were living in the United States at the time. Because many worked in construction during the housing boom and lived in temporary housing arrangements, it may have been particularly difficult to accurately account for them in census surveys. However, when the Great Recession and housing crisis hit, many of these temporary workers went home or stopped coming to the U.S. in the first place, and coverage error declined. By 2010, the coverage error may have been as low as 6 percent.

If current levels of coverage error for all unauthorized immigrants were as high as 26 percent, then the number living in the country could be as high as 13 million. But if coverage error were as low as 6 percent, then the figure could be as low as 10.3 million.

What this boils down to is that we have a pretty good idea of the number of unauthorized immigrants living in the United States. It most likely falls within a narrow range somewhere between 10.3 million and 13 million. If coverage error has declined as much as we think it has, then the truth is at the lower end of this range. Despite widespread beliefs, unauthorized immigration is not increasing out of control and certainly is not as high as 30 million. Instead, it has probably really has stabilized somewhere around 11 million.

The Conversation

Jennifer Van Hook is a Liberal Arts Research Professor of Sociology and Demography at Pennsylvania State UniversityThis article was originally published on The Conversation. Read the original article.

Experts available to media for presidential debate analysis

AmericaAs Hillary Clinton and Donald Trump take to the stage again Wednesday evening in the final presidential candidate debate, Penn State experts will be watching along with the rest of the general public, and they’ll be availably immediately afterward to give their analysis to media.

Penn State experts are available to comment on the debate by texpertise topic:


Shoba Sivaprasad Wadhia, a clinical professor of law and director of the Center for Immigrants’ Rights, will be watching the debate and is working to fact check the candidates’ statements regarding immigration law and policy.


Michael Nelson, assistant professor of political science, specializes in American politics, state politics, and judicial politics. His research examines the effects of judicial elections on the development of the law as well as the determinants and effects of public support for state and federal courts in the United States.


— Nichola Gutgold, professor of communication arts and sciences, is an expert on women in politics. She can speak about past female political candidates and barriers women face today. She is the author of “Madam President: Five Women Who Paved the Way.”

— Christopher Beem, manager of the Penn State McCourtney Institute for Democracy, can speak generally about American politics, the state of democracy and the political debate. He is the author of “Democratic Humility” and four other books.


— Dennis Jett, professor of international affairs, can speak to the topic of securing America. He is a former American ambassador who joined the School of International Affairs after a career in the U.S. Foreign Service that spanned 28 years and three continents. His experience and expertise focus on international relations, foreign aid administration, and American foreign policy.


— Anne McKenna, visiting assistant professor of law, is available to talk about key cyber, social media, electronic privacy and email issues in the Presidential Election. She is a nationally recognized trial attorney and author in cyber, privacy, electronic surveillance and cellular law. She can discuss the use of social media in the election by both parties, the influence of hacking in this election and the broader implications of online privacy and security.

Sascha Meinrath is the Palmer Chair in Telecommunications at Penn State and director of X-Lab, an innovative think tank focusing on the intersection of vanguard technologies and public policy. Professor Meinrath is a renowned technology policy expert and is internationally recognized for his work over the past two decades as a community internet pioneer, social entrepreneur and angel investor.


— Robert Speel, associate professor of political science, can speak generally about the debate and historical moments in past presidential debates. He recently wrote an article for The Conversation about the five key debate moments that altered the course of a presidential race. His research interests include elections and voting behavior, state and urban politics, Congress and the Presidency, and public policy.

Mark Major is a senior lecturer in the department and the author of “The Unilateral Presidency and the News Media: The Politics of Framing Executive Power.” He specializes in the American presidency and political communication. He recently wrote an article for The Conversation about President Obama’s use of unilateral powers compared to other presidents.


For more information or direct phone numbers for the experts, please contact News and Media Relations at 814-865-7517 or

Five key debate moments that altered the course of a presidential race

Robert Speel | Pennsylvania State University


Every presidential election year in my American Political Campaigns and Elections course, I get an opportunity to spend a full lecture discussing with students some of the famous moments from historic presidential debates.

Robert Speel

Robert Speel

I explain to students that while the presidential candidate debates are supposed to be about presenting policy alternatives to undecided voters, almost no one pays any attention or remembers what the candidates say about policy.

Instead the media covers the debates and voters interpret the debates in a winner and loser format. Which candidate connected to voters the best? Who had the best zinger or inspirational line?

Some famous moments in debate history have reinforced the public’s negative perceptions of candidates, while other key moments have helped dispel such notions.

Here are five from past presidential debates, chosen for their impact on the election campaign and outcome.

1960: Kennedy-Nixon

In 1960, Richard Nixon had served as the Republican vice president for eight years after six years in Congress. Senator John Kennedy had served in Congress for 14 years, but was only 43 years old with a youthful appearance and image. Using the still relatively new medium of television, Kennedy and Nixon agreed to the first general election presidential candidate debates in American history, four in total. (The famous Lincoln-Douglas debates of 1858 were for a U.S. Senate seat; they did not debate in the 1860 presidential election.)

Kennedy’s goal during the debates was to ease voters’ fears that he was too young and inexperienced to serve as president. Nixon, on the other hand, repeatedly emphasized his own foreign affairs experience in campaign advertising.

While Kennedy appeared comfortable and confident in front of television cameras, Nixon famously declined to wear makeup, ended up sweating under the camera lights, and sometimes shifted his eyes, unsure where to look. While the legend that Kennedy won the debate among television viewers and Nixon won the debate among radio listeners may be a myth, the debate did dispel the image that Kennedy was somehow less prepared than Nixon to be president.

Richard Nixon wipes his face during the first televised presidential debate.

1980: Carter-Reagan

Democratic President Jimmy Carter had presided over foreign policy crises in 1979 – including the taking of hostages from the U.S. Embassy in Iran – and persistent economic problems during his presidency. Some voters perceived him as ineffective. Meanwhile, Ronald Reagan, the former governor of California, was calling for a nuclear buildup during the Cold War and had a history of criticizing entitlement programs. Some also thought he was too old to lead the nation. (At age 69, Reagan would become the oldest man ever elected president.)

The debates were delayed due to disagreement over whether John Anderson, an independent candidate whose polling numbers had dropped from over 20 percent to under 10 percent in the weeks before the election, should be allowed to participate. Carter and Reagan finally agreed to one debate a week before the election.

At the debate, Carter tried to reinforce Reagan’s image as a war hawk willing to start nuclear wars. In a key moment, Carter said that he had discussed politics with his 13-year-old daughter, Amy, to ask her what was the biggest issue in the election, and she answered “nuclear weaponry.”

But Reagan came away with the most memorable moment. After Carter mentioned Reagan’s past opposition to Medicare, Reagan tilted his head, smiled and said, “There you go again” to audience laughter – perhaps an attempt to dispel Carter’s attempts to make Reagan look dangerous.

In his closing statement, Reagan then spoke to voters through the cameras and asked “Are you better off than you were four years ago?,” alluding to the state of the economy. Polls in the last week indicated a major surge in support for Reagan.

‘There you go again.’

1984: Reagan-Mondale

Before the 1984 election, Reagan was 73 years old, already the oldest president in American history. Age was a potential issue for voters. During the first debate with Walter Mondale, the 56-year-old former vice president and former two-term U.S. senator, Reagan occasionally lost focus and seemed confused. After that first debate, Reagan’s large lead over Mondale in polls began to narrow.

During the second debate, a moderator asked Reagan whether his age should be an issue in the campaign. Reagan answered, “I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent’s youth and inexperience.”

The audience laughed – Mondale included – and the media eagerly replayed and reprinted the joke. Reagan won in November in a landslide.

During a 1984 campaign debate, Reagan turned the issue of age on its head.

1992: Bush-Clinton-Perot

The 1992 presidential election involved the only three-candidate general election debates in American history. Incumbent George H.W. Bush needed to overcome an image that he was somewhat out of touch with recent problems in the American economy, an image partly shaped by media reports that Bush had seemed amazed at the technology of supermarket bar code scanners, which had been around since 1976.

In contrast, Clinton had famously told an upset voter earlier in the year that “I feel your pain.” Ross Perot, a Texas multibillionaire, was not a Bush fan and was running a populist and centrist campaign focused on balanced budgets and opposition to trade agreements.

The second of three presidential debates that year was held in a town meeting format. During the debate, Bush was seen on camera checking his wristwatch twice, giving viewers the impression that he would rather be somewhere else. And when an audience member asked a question that made no sense, mixing up the national debt and economic recession, Bush told the audience member that he didn’t understand her question, while Clinton walked over to her and invited her to tell him more about her economic problems.

This debate reinforced voter images of the candidates: Bush seemed less interested in the problems of average people, while Clinton expressed compassion toward voters.

Clinton expresses compassion.

2012: Obama-Romney

At the first debate of 2012, Obama did not appear as energetic as usual and didn’t give any of the snappy answers that viewers expect and that tend to dominate media attention after debates. Following the debate, polls indicated that Romney had taken a small lead over Obama.

But at the second debate, when Romney asserted inaccurately that Obama had not referred to the attack on the Benghazi consulate in Libya as an “act of terror” for two weeks, moderator Candy Crowley interjected to correct Romney’s mistake. Obama chimed in “Can you say that a little louder, Candy?” as Obama supporters at home reacted in delight at Romney’s embarrassment. Romney compounded his unfortunate choices of words at the debate by noting that as governor, he had received “whole binders full of women” to consider for positions in state government.

The awkward comment became an instant joke, with dozens of internet memes circulating in the days after the debate.

Obama gets an assist from Candy Crowley.

Looking ahead

While we don’t yet know which comments or events at this year’s debates may affect the outcome of the election or remain memorable, we can expect that candidates will do their best to dispel negative images of themselves – while reinforcing negative images of their opponents.

Watch for Hillary Clinton to focus on insulting comments that Donald Trump has made about people or groups and to focus on some of Trump’s past business practices: Trump University, the Trump Foundation and his casino businesses. She will also likely try to expose some of Trump’s populist claims – like Mexico paying for a wall on the border – as devoid of substance. At the same time, she will try to reinforce her own image as an experienced political leader.

And watch for Trump to focus on past errors made by Clinton, like her foreign policy judgment, her use of a private email server and meetings with donors to the Clinton Foundation. Trump may also attempt to dispel his image as being inexperienced in world affairs by appearing calm and confident in his assertions, while pointing to past mistakes American leaders have made. He may also try to focus on some substantive and moderate policy proposals to distinguish himself from the bellicose firebrand he appears to be on the stump.

The campaign staffs of both candidates have likely been rehearsing some zingers that could be used in the first debate. But candidates need to be careful about making them sound spontaneous. If they sound rehearsed, they’ll reinforce one of the worst qualities people can think of a candidate: that they’re fake.The Conversation

This article was originally published on The Conversation. Read the original article.

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