That stark contrast conveys, to economists, two important facts. One is that Mexicans are supplying a skill level that is much in demand. It doesn't just seem that Americans don't want to be hotel chambermaids, pick lettuce or repair roofs; it's true. Most gringos are too educated for that kind of work. The added diversity, the complementariness of skills, that Mexicans bring is good for the economy as a whole. They perform services that would otherwise be more expensive and in some cases simply unavailable.
The Americans who are unskilled, however, must compete with a disproportionate number of immigrants. One of every four high-school dropouts in the U.S. was born in Mexico, an astonishing ratio given that the proportion of Mexicans in the overall labor force is only 1 in 25. [...]
That's the theory. But economists have had a hard time finding evidence of actual harm.
