Whereas many secondary cities were able to economically specialize in certain products and develop a comparative advantage at the national level over time, they proved to be overly dependent on vertical specialization which characterized their economic organization. Economies of scale worked within a framework of vertical specialization, but when these industries were challenged by lower labor costs in Latin America and later in Asia, they were unable to compete. De-industrialization first hit North America and Europe and later Latin America as jobs moved to China and other African and Asian countries.