An increase in the supply of labor lowers wages only if nothing else changes. But when immigrants enter the workforce two very important other things change. First, immigrant workers spend or invest their earnings, both of which activities increase the demand for labor – thus putting upward pressure on wages. By focusing only on immigrants’ effect on the supply of labor, Mr. Burwell overlooks immigrants’ effect on the demand for labor.
A second change is one that was emphasized by Adam Smith: larger supplies of workers, as well as more consumers of the economy’s output, lead to greater specialization. Jobs change. As Smith explained, this greater specialization makes workers more productive. This increased productivity, in turn, causes wages to rise.
Peter Turchin would disagree. In Ages of Discord, he finds a strong historical correlation between periods of high rates of immigration and stagnant wages for ordinary workers. I have read through Turchin’s book once, and I mean to write a review. But I keep procrastinating. I am tempted to say that the book, while it appeared to be very interesting on a first pass, is un-rereadable. The data that lands in Turchin’s charts takes a very circuitous route to get there, and it hard for me to stay on top of the relationship between the underlying data and what Turchin says that they represent.