Pro-migration economic studies do not support migration because those studies leave out most of the economic costs, especially long-term economic costs. In short, those studies are junk science.
He concludes, "I do not think that the three effects I listed here (and perhaps there could be others) are sufficiently strong to negate the positive economic effects."
Perhaps there could be others?
You mean like the proven facts of massive moral harms, including massive dysgenic effects, and massive replacement of good cultures with horrific cultures?
Plus the costs of relentless ad hominem attacks like Milanovic's "xenophobia."
The moral costs of mass nonwhite migration are hundreds of times greater than any asserted economic benefits.