This is the VOA Special English Education Report.

Not all college teachers are professors. In fact, not even all professors are full professors. Many are assistant or associate or adjunct professors. This week in our Foreign Student Series, we sort out academic titles at American colleges and universities.

Professors usually need a doctorate degree. But sometimes a school may offer positions to people who have not yet received their doctorate.

Such a person would be called an instructor until the degree has been completed. After that, the instructor could become an assistant professor. Assistant professors do not have tenure.

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

Assistant professors generally have five to seven years to gain tenure. During this time, other faculty members study the person's work. If tenure is denied, then the assistant professor usually has a year to find another job.

Candidates for tenure may feel great pressure to get research published. "Publish or perish" is the traditional saying.

An assistant professor who receives tenure becomes an associate professor. An associate professor may later be appointed a full professor.

Assistant, associate and full professors perform many duties. They teach classes. They advise students. And they carry out research. They also serve on committees and take part in other activities.

Other faculty members are not expected to do all these jobs. They are not on a tenure track. Instead, they might be in adjunct or visiting positions. A visiting professor has a job at one school but works at another for a period of time. An adjunct professor is also a limited or part-time position, to do research or teach classes. Adjunct professors have a doctorate.

Another position is that of lecturer. Lecturers teach classes, but they may or may not have a doctorate.

And that's the VOA Special English Education Report, written by Nancy Steinbach. This is the twenty-seventh week of our Foreign Student Series on higher education in the United States -- with more to come.

Our series is archived with audio files and transcripts at voaspecialenglish.com. And our e-mail address is special@voanews.com. If you write to us, please be sure to include your name and country. I'm Steve Ember.