 |
| Authors of a controversial population study describe their methods |
An academic
paper published on September 21 by the academic journal PLOS One
claims that as of 2016 the unauthorized population was between 16.2 million and
29.5 million. The number, proposed by three scholars associated with the Yale School of
Management, is about twice as high as the estimated range of 10.8 million to
12.1 million used by most demographers, including those at the Migration Policy
Institute (MPI), the Pew Research Center, and the government’s own Department
of Homeland Security (DHS).
PLOS One simultaneously published a paper
by MPI researchers sharply criticizing the Yale study.
Most demographers estimate the undocumented population’s
size by applying a residual method
to data from the Census Bureau, DHS, and DHS’s predecessor, the Immigration and
Naturalization Service (INS). The data is compared to other public records to
adjust for the well-known phenomenon of underreporting by undocumented
immigrants. The Yale study takes a different approach: the researchers use
government records and projections to estimate the inflow of unauthorized
immigrants over the border and through overstays and then subtract an estimate
of the immigrants’ outflow. (Some of the government’s estimates are discussed here
and here.)
But as the MPI paper notes, it’s only in the past few years
that DHS has been providing enough data on unauthorized inflows and outflows to
justify estimates. The Yale study projects current estimates back to 1990,
ignoring some of the major changes in immigration patterns that resulted from
increased border enforcement over the 26 years from 1990 to 2016. The backwards
projection method also means that any errors in the estimates for an earlier
year are compounded in each subsequent year—in contrast to the residual method,
which allows for researchers to make a fresh estimate each year.
The MPI study notes that the “residual method was put to the
real-world test successfully in the 1980s,” when “estimates generated with this
methodology” turned out to be “largely similar to the actual number of
unauthorized immigrants who came forward to get legalized” through the 1986
amnesty. (We make the same point in the first chapter of The Politics of
Immigration’s second edition.)
How Will the Right Use the New Study?
Anti-immigrant forces have been relatively silent so
far—probably because of the current media attention to various
crises
for the Trump administration—but it seems likely they’ll be citing the Yale
study in the future: anti-immigrant groups and rightwing pundits have spent
years exaggerating the size of the undocumented
population. For example, author and TV personality Ann Coulter regularly puts
the number of undocumented immigrants at 30
million.
The rightwing position already gets a good deal of popular
support because of widespread misperceptions about immigration. In 2011 Transatlantic
Trends researchers asked people in the United States to estimate the
proportion of immigrants here. On average, U.S. respondents thought
immigrants—naturalized, documented and undocumented—made up 37.8 percent of the
U.S. population at a time when the actual proportion was under 14 percent. (If we used the Yale study's estimates, the total foreign-born population would still be less than 18 percent.)
Inflated rhetoric by politicians leads to inflated numbers
in people’s minds, and the media often fail to counter this with coverage of
some important statistics. How do Coulter and fellow pundit Michelle Malkin get
away with their claim that the 11 million figure must be wrong? Their supposed
evidence is that the number hasn’t changed over the last decade. This seems
convincing because the media constantly report figures on border apprehensions.
So the public knows that unauthorized migrants are continuing to enter the
country, and it seems like a common-sense conclusion that the undocumented population
must be increasing. The media rarely note that undocumented immigrants are also
leaving, at the about same rate as they’re entering.
Interestingly, one leading immigration-restrictionist
organization, the Center for Immigration Studies (CIS), immediately rejected
the Yale study. A September 22 CIS
article expressed agreement with the MPI’s critique and added some
additional points. For example, CIS estimates that if the Yale figure was
correct, the Department of Education’s 2014 count of children enrolled in
schools would have been about 1 million higher. (The Southern Poverty Law
Center lists CIS as an anti-immigrant
hate group; however, CIS statistics tend to be accurate, although the
group’s analysis of them is often questionable.)
The study’s authors seemed a little defensive in a September
21 video
presentation posted by Yale Insights to explain their methods The
authors insisted that they had no political agenda to promote. Co-author Edward
H. Kaplan pointed out that the study could be used to counter efforts to depict
undocumented immigrants as criminals, since if the undocumented population was
doubled, the undocumented crime rate would fall in half.
(This might actually undercut the report. Based on
statistics from Texas, the Cato Institute’s Alex Nowrasteh has determined that
undocumented immigrants are convicted of crimes at a lower rate than the native
born but at a higher rate than immigrants with legal status, who tend to be
older, more affluent and less likely to be arrested. The Yale study would have
the improbable
result that undocumented immigrants have same conviction rate as
authorized immigrants.)
