Researchers have examined the size of economic losses caused by current restrictions on international migration, and the findings are frankly remarkable. As development economist and world-leading migration expert, Michael Clemens, puts it, “The few estimates we have should make economists’ jaws hit their desks.”
In his review of the available evidence, Clemens reports that an expansion of international migration, realized through the removal of some (read: not all) restrictions on people’s movement, could generate economic gains equivalent to 20 percent of global GDP. And that’s a conservative estimate - some studies place the figure closer to 60 percent.