Quite a few of his readers then attempted to acquaint him with the data in a lengthy and impressively documented comments thread, but apparently Cowen has not found this data "useful" in supporting his preconceptions.
Of particular value were the comments made by a Ph.D. student in economics calling himself "Teller," who is himself an immigrant from a Third World country.
Here’s a sample of his many contributions to the comment thread.
Getting data on illegal immigrants is particularly difficult, so he had the clever idea of looking at Census data on individuals born in Mexico, of whom many were, at least originally, illegal aliens.
More facts (evil evil facts)
I am going to, using the US-2000 census, compare the 250 million Natives, the 9.2 million Mexicans foreign born, and the 22 million other immigrants.
(the 22 are obviously all foreign born minus Mexican foreign born)
Let us start with labor force participation of those hardworking Mexicans. Natives 60.2% Other Foreign-born 57.1% Mexican 54.3%
Per capita Income? Natives $22,000 Other Foreign-born $25,000 Mexican $13,000
Perhaps the best proxy for success in society overall and welfare dependency in particular, is the rate of poverty Natives 8.3% Other Foreign born 11.4% Mexican 24.4%
Share speaking English at home, as good a measure of assimilation as anything Natives 91% (remember 8% of natives are already Hispanics) Other Foreign born 22% Mexican 5.6%
Education? Surely only a nazifacistracist uncultured bigot would suggest Mexican immigrants are not well educated.
Share of population with no high school diploma Natives 17% Other Forign born 25% Mexican 70%(!)
This is the share that have college education: Natives 25% Other Foreign born 32% Mexicans 4%(!!)
Lots more of "Teller's" highly informative comments can be found here.