What impact has immigration had on the U.S. economy over these last few decades? How will immigration reform change the economy for native‐​born Americans? These vital questions must be answered so that immigration reform produces a good outcome for Americans. With few exceptions, immigrants expand the size of the economic pie by creating businesses and expanding the scope and quantity of economic production—with mostly positive affects on Americans. To understand this complex phenomenon, different types of immigrants—those who are higher skilled and those who are lower skilled—and their various impacts on the American economy will be examined in detail.