Not all college teachers are full professors. Many are assistant or adjunct professors. This week in our Foreign Student Series, we discuss academic titles in American higher education.

Adjunct professor Charles Varani at Western Oregon University in Monmouth in 2005

Professors usually have doctorate degrees. But college students may be taught by instructors who have not completed their doctorate degrees. After that, the instructor could become an assistant professor. Assistant professors do not have tenure.

A professor with tenure cannot be easily dismissed. Such appointments are permanent.  Those hired with the understanding they will seek tenure are said to be "on the tenure track." Assistant professor is the first job on this path.

Assistant professors have five to seven years to get tenure. They must teach, carry out research and publish their findings.  Other professors then study the work. If tenure is denied, the person usually has a year to find another job. An assistant professor who receives tenure becomes an associate professor and may later be appointed a full professor.

Professors on the tenure track teach classes, advise students and carry out research. They also serve on committees and take part in community activities.

Other teachers are not expected to do all this. They are not on a tenure track. They are called adjuncts.

An adjunct professor is hired to teach for a limited time, usually one semester. Adjunct professors may have a doctorate. But they receive lower pay than those on the tenure track and have no job security.

The American Association of University Professors says sixty-eight percent of all teacher appointments at American colleges today are adjuncts. College officials say one reason is low budgets. Another is having the freedom to change teachers as courses become more or less popular. They also say part-time adjuncts can provide real world experience for their students.

But the AAUP and other college officials say too many adjuncts mean lower educational quality. They say adjuncts do not have the time or support to help students outside class. And they say fewer tenure track positions mean fewer people to work with students, create new courses and serve on committees.

And that's the VOA Special English Education Report, written by Nancy Steinbach. Transcripts, MP3s and podcasts of our programs are at voaspecialenglish.com. I'm Shirley Griffith.