Preference System (Immigration Act of 1990) refers to the nine classes or categories under which the family-sponsored and employment-based immigrant preference visas are granted or distributed since 1992. The family-sponsored preferences are:
1. Unmarried sons and daughters of U.S. citizens;
2. Spouses, children, and unmarried sons and daughters of permanent resident aliens;
3. Married sons and daughters of U.S. citizens; and
4. Brothers and sisters of U.S. citizens.
The employment-based preferences are:
1. Investors or employment creation immigrants;
2. Priority workers or those individuals who possess extraordinary abilities, outstanding professors and researchers, and certain multinational executives and managers;
3. Professionals with advanced degrees or foreigners with exceptional ability;
4. Skilled workers, professionals without advanced degrees, and needed unskilled workers; and
5. Special immigrants.