Conflicting New Estimates of Illegal Immigration

Migrants return to Mexico after attempting to illegally cross the border wall into the United States in Tijuana, Mexico, November 25, 2018. (Adrees Latif/REUTERS)
Trump critics touted a new Pew study that claimed a decline, but a recent Yale study tells a different story.

As a general rule of thumb, scholarly population studies aren’t fodder for newspaper headlines. But when the Pew Research Center issued a new study this week about the number of illegal immigrants in the country, it was greeted by the mainstream media with the sort of acclaim which is only reserved for stories that can make President Donald Trump look bad.

Nevertheless, the news from Pew was remarkable. Much of the debate about illegal immigration has been driven by the idea that the number of those whom sympathizers dub “undocumented” is enormous. That’s the conceit of much of Trump’s comments. Not long after declaring his candidacy for the presidency in 2015, he declared the number of illegals to be as high as 30 million and growing all the time due to a porous border and broken enforcement system, even though most of those who claimed to be experts on the topic claimed there were only 11 million. Yet according to Pew’s latest work, rather than getting larger, the population of illegals is shrinking.

According to Pew, the number of illegals was estimated at 10.7 million in 2016, down from the last generally accepted estimate of 11.3 million and a sharp decline from a peak of 12.2 million in 2007. Pew researchers claim that the overall total of those entering and staying illegally is down and that the nature of that population is also changing. The study said a much larger percentage of them is made up of those who overstay visas rather than those who sneak into the country. Those who make up that 10.7 million were also said to be more likely to be longstanding residents of the United States, with many of those who were here for shorter periods going back to their countries of origin.

The political implications of their work would mean that not only was the problem not as serious as Trump has indicated, it’s largely resolving itself. Seen from this perspective, though still too large a population to be simply rounded up and deported, as some immigration hawks might want, the number of the “undocumented” was therefore manageable, making amnesty plans — whether the more limited DACA scheme for “dreamers” who had been brought here as children or more generous schemes — more rational.

That would allow concerns about border security and the ongoing flow of such people into the country to be seen in a different light. Rather than a serious problem, talk about illegals could be dismissed as the product of unreasonable fears whipped up into hysteria by the rhetoric of cynical politicians such as the president.

But there was one thing missing from the discussion about the Pew survey: It contradicted another study that had been recently published with very different results.

In September, the Yale University School of Management released a study with breathtaking implications.

Rather than dovetailing with Pew, a trio of Yale scholars came to sharply different conclusions. According to them, the number of illegals was far greater than previously thought. Their study of demographic and immigration-operations data led them to believe that there are approximately 22.1 million illegals currently living in the United States, a result the authors said surprised them. Shocked by their findings, the authors then deliberately altered the parameters of their study to get a more conservative estimate of illegals. But even that attempt yielded a result of 16.7 million.

The study was originally intended as a “sanity check” on the widely accepted numbers cited by Pew. But what the Yale researchers found was that the assumptions at the foundation of those studies were faulty. Employing all existing data figuring in rates of death, immigration, visa overstays, and other available demographic data, they attempted to put together a viable model for answering the question about the number of those living here illegally.

While there were some areas in which their work overlapped with other studies in terms of detecting a decline of some sort after the recession of 2008 made the United States a less attractive place to those looking for work, this population has been relatively stable since then.

But their differences with other studies stem from the fact that they believe there is strong evidence many of those who have worked on the problem underestimate. While both sides of this argument are measuring statistically valid levels of inflow and outflow in much the same way, those who have come up with lower estimates are failing to take into account that those who seek to enter illegally are doing their best not to be detected or in some way be accounted for in the data. The Yale group took the uncertainty factor more seriously and has produced a very different model. As the summary of their report stated: “After running 1,000,000 simulations of the model, the researchers’ 95% probability range is 16 million to 29 million, with 22.1 million as the mean.”

The potential implications of their work are enormous.

The first and most obvious point is that it was irresponsible for the media to trumpet the Pew results without mentioning that the Yale group contradicted them. Indeed, one needn’t believe that all liberal media is “fake news” to conclude that the lack of interest in the Yale study, both when it was published and as a comparison to what Pew produced, was because much of the media was not interested in a work that essentially backed up some of what Trump has been saying.

Second, if there are 22.1 million illegal immigrants here, with the possibility that there actually far more, then the complacency about the issue by those who accuse Trump of scaremongering can no longer be portrayed as being the adult response to the issue.

Third, while the Yale study may back up arguments that claim illegal immigration is a severe problem, it doesn’t necessarily validate some of the fears about that population. As the authors noted, if the total of illegal immigrants is approximately double what we’ve assumed, then that means the crime statistics — a number that is not in dispute — actually paint a much more positive portrait of illegal immigrants. Essentially, that would mean that although some notorious incidents have focused the country on the possibility that criminals and murderers have gotten into the United States without permission and sometimes even been allowed to stay because of misguided sanctuary-city laws, double the population means that the crime rate for illegals might actually be half of what is generally claimed. The same can be said concerning the discussion about how many jobs illegals are taking away from legal residents.

But whatever those numbers mean for those specific issues, the possibility that the total population of illegal immigrants is much higher than is assumed ought to transform arguments about border security and amnesty.

The spectacle at the border as those seeking to enter illegally, or to do so on bogus claims of seeking asylum — which will lead to their immediate release — has refocused the country on the question of illegal immigration. The Yale study makes it clear that whatever one may think of Trump — or if caravans from Honduras constitute an “invasion” — the conventional wisdom about illegal immigration may be wrong. If the Yale scholars are anywhere close to being right, the problem needs to be looked at as being far more serious than even many conservatives assumed.


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