However, Freeman and other economists draw attention to two major considerations. First, how much real incomes of native workers drops depends upon how flat or steep is the labor demand curve. Freeman cites one representative study of the United States that found a 10 percent increase in the fraction of immigrants lowered native workers real incomes by at most 1 percent. Even George Borjas – who has found stronger real wage erosion than most researchers – finds a response of at most 3 percent. And several studies suggest no effect. Thus, representative labor demand curves are fairly flat, dampening the decline in real wages of workers. The second major consideration is that the demand curve itself may shift. If it shifts up (for reasons to be discussed shortly), real wages of native workers may actually rise.
That is, an increase in immigrants may actually help earnings of native workers.