This process can be analyzed at the state level (see Peri and Sparber 2009). The analysis begins with the well-documented phenomenon that .-born workers and immigrants tend to take different occupations. Among less-educated workers, those born in the United States tend to have jobs in manufacturing or mining, while immigrants tend to have jobs in personal services and agriculture. Among more-educated workers, those born in the United States tend to work as managers, teachers, and nurses, while immigrants tend to work as engineers, scientists, and doctors. Second, within industries and specific businesses, immigrants and .-born workers tend to specialize in different job tasks. Because those born in the United States have relatively better English language skills, they tend to specialize in communication tasks. Immigrants tend to specialize in other tasks, such as manual labor. Just as in the standard concept of comparative advantage, this results in specialization and improved production efficiency.