Identifying illegal aliens in Census Bureau data is a challenging task. Researchers must gather the limited amount of outside information they have about the illegal population, then make educated guesses about the legal status of non-citizens in the data. Given all the uncertainty, it's important to assess the face validity of the results — in other words, are they plausible?
That's where a new Cato Institute analysis went wrong. Intending to demonstrate the importance of immigrants to the healthcare system, Alex Nowrasteh and Michelangelo Landgrave reported that over 42,000 physicians in the United States are illegal aliens.
Take a moment to consider the implausibility of that number. The Center for Migration Studies (CMS) estimates 7,427,035 illegal immigrants in the labor force, based on the same 2018 American Community Survey (ACS) data that Cato used. If Cato's illegal-physician count is correct, then about 0.6 percent of all illegal workers are doctors. But only 0.5 percent of natives in the labor force are doctors — 653,865 native-born doctors out of 135,783,619 workers. In other words, illegal workers are supposedly more likely to be physicians than native workers!
Here is another way to look at it: The 2018 ACS shows a total 66,065 non-citizen physicians who arrived in the United States since 1980.1 This is around the earliest time that any current illegal alien could have arrived due to the IRCA amnesty.2 Nowrasteh and Landgrave would have us believe that nearly two-thirds of them are here illegally.3
Their illegal counts for some other healthcare occupations also constitute an implausibly high share of post-1980 non-citizens. In the table below, the first three columns are from Cato's Table 1, and the last two columns (in red) are our calculations from the same data. For example, 88 percent of all post-1980 non-citizen nurse-anesthetists are supposedly illegal, as are 71 percent of physician assistants.
Healthcare Workers by Occupation
|Column 1||Column 2||Column 3||Column 4||Column 5|
Who Arrived in
1980 or Later
|Illegal Share of
Who Arrived in
1980 or Later
Source: Columns 1, 2, and 3 from are Table 1 of "Immigrant Health Care Workers
In addition to obtaining an advanced education that is out of reach for most illegal aliens, doctors and other health care providers also need to be licensed, yet few states offer licenses to people who are not authorized to work in the country. Moreover, like doctors, many of these occupations (e.g. nurse-anesthetists, nurse practitioners, and physician assistants) typically require Drug Enforcement Agency registration so they can dispense drugs. In short, many of Cato's numbers do not just stretch credulity, they break it.4
The licensing requirement is the primary reason both Pew and the CMS, which produce the two leading demographic profiles of the illegal population, automatically count physicians as legal.5 CIS follows the same rule, and it is why we do not report an estimate for illegal doctors and other highly regulated medical professions in our analysis of occupations. This is not to say that the number of illegal alien doctors or other high-skilled medical practitioners is exactly zero. Surely there are some, but no probabilistic method will be able to count them reliably.
1 Cato includes in their numbers those employed, those unemployed, and those totally out of the labor force (neither working nor looking for work). The ACS reports occupations for those not working if they were employed in the prior five years. Though it impacts the numbers only slightly, the inclusion of those totally out of the labor force is surprising since these individuals are by definition not practicing medicine. Nonetheless, the post-1980 non-citizen figures we report follows Cato's definition of healthcare professional.
2 The Cato healthcare report links to another Cato report to explain how they determine legal status. That report states that they followed the method of another researcher, Christian Gunadi, and the Cato authors "identified an immigrant as lawfully present if he or she met any of the following criteria: the immigrant arrived after 1980." This must be a typo as "after" should read "before". Gunadi is certainly clear in his report that he considers anyone a legal immigrant if they arrived before 1980.
3 Cato did not adjust upward the number of illegal immigrants identified in the data. We know this because the number of legal and illegal immigrants they report separately add up to the total number immigrants in the ACS.
4 There are occupations, such as medical assistants, that typically require only modest training and no licensing, where significant numbers of illegal immigrants do work. So their numbers in that category are not unreasonable.
5 Robert Warren of the Center for Migration Studies (CMS) noted in an email on May 13, 2020, that the estimates developed by CMS employ "logical edits" to the ACS data that exclude doctors as possible illegal immigrants. The lack of logical edits in the healthcare field is presumably the main reason Cato came up with implausible numbers.