Yale University Finds 22 Million Illegal Immigrant
2018 Yale Study Finds Twice as Many Undocumented Immigrants as Previous Estimates
Generally accepted estimates put the population of undocumented immigrants in the United States at approximately 11.3 million. A new study, using mathematical modeling on a range of demographic and immigration operations data, suggests that the actual undocumented immigrant population may be more than 22 million.
Using mathematical modeling on a range of demographic and immigration operations data, the researchers estimate there are 22.1 million undocumented immigrants in the United States. Even using parameters intentionally aimed at producing an extremely conservative estimate, they found a population of 16.7 million undocumented immigrants.
The results, published in PLOS ONE, surprised the authors themselves. They started with the extremely conservative model and expected the results to be well below 11.3 million.
“Our original idea was just to do a sanity check on the existing number,” says Edward Kaplan, the William N. and Marie A. Beach Professor of Operations Research at the Yale School of Management. “Instead of a number which was smaller, we got a number that was 50% higher. That caused us to scratch our heads.”
Jonathan Feinstein, the John G. Searle Professor of Economics and Management at Yale SOM, adds, “There’s a number that everybody quotes, but when you actually dig down and say, ‘What is it based on?’ You find it’s based on one very specific survey and possibly an approach that has some difficulties. So we went in and just took a very different approach.”
The approach in the new research was based on operational data, such as deportations and visa overstays, and demographic data, including death rates and immigration rates. “We combined these data using a demographic model that follows a very simple logic,” Kaplan says. “The population today is equal to the initial population plus everyone who came in minus everyone who went out. It’s that simple.”
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