immigrants. Finally, we compare U.S. approaches to immigration with those of other countries.

A Word about Terminology

For clarity's sake we first define a few terms that will be used in this volume. Immigration and emigration generally refer to movements of people into and out of the United States. Foreign-born persons who enter the United States for residence are immigrants;1 residents of the United States, whether native- or foreign-born, who leave the country to settle elsewhere are emigrants. Net migration is the difference between the two. If the number of people entering the United States exceeds the number who leave, net migration will be positive and immigration will contribute to America's population growth.

A distinction is made between legal and illegal (or undocumented) immigrants. Among those who intend to reside permanently in this country, legal immigrants apply for and receive permanent resident visas, "green cards" allowing them to live here indefinitely. Although illegal immigrants are often lumped together as if they formed one homogeneous group, people become illegal immigrants in three ways. The first way is by entering the country illegally; they enter without inspection and at some place other than a lawful point of entry, usually across a land border. The second way is by staying beyond the authorized period after their legal entry, as some foreign students do. And the third way is by violating the terms of their legal entry; tourists become illegal immigrants by taking jobs here.

Most people who enter the United States legally do not intend to become permanent residents. These people, referred to as nonimmigrants by the Immigration and Naturalization Service (INS), are authorized to stay in the United States for a specified length of time. The types of visas granted reflect the purpose of the visit to the United States, of which tourism is by far the most dominant. In addition, foreign students may study in the United States for several years; foreign diplomats and foreign members of the staffs of international organizations also have nonimmigrant status. This report largely ignores nonimmigrants, except when pertinent to its focus on the economic and demographic consequences of immigration.2


The Immigration and Naturalization Service (INS) has a more restricted use of the term "immigrant." In INS usage, an immigrant is an alien admitted to the United States as a lawful permanent resident. Under the INS definition, such undocumented aliens or foreign students on a temporary entrance visa are not immigrants, even though they may be enumerated in the decennial census and included in federal government surveys. We note in this report when there a different usage for the term "immigrant."


Although we do not explicitly address this group, nonimmigrants are indirectly included to some extent in our report because they are included in census data, pay taxes, influence public opinion polls, and constitute a stock of persons who may become illegal immigrants.

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