There are several different types of professor jobs that academics can pursue on the path to, or in lieu of, a career as a college or university professor. Some of these professions include teaching assistant (TA), associate professor, teaching fellow (TF), and adjunct professor. These professor jobs require specific academic credentials that may vary by country or academic institution. Some of these positions may also allow the incumbent to reach tenure, which provides him or her with a contractual level of job security and the opportunity to move up in the ranks of professor jobs.
Sometimes referred to as tutors or graduate teaching assistants (GTAs), TAs are graduate students employed by college or universities to assist professors with course instruction. A TA will provide support to the professor during lectures, grade students' work, and may also conduct tutorials or labs independently. Undergraduate teaching assistants (UTAs) are part of a sub-category of TAs who hold a bachelor's, or undergraduate, degree and may be paid by course credit rather than the fixed salary which TAs receive on a contract basis. A TA who has received tenure or established a track record of academic accomplishments set by the college or university is promoted to the position of associate professor.
Unlike a TA, a teaching fellow (TF) is an academic who holds a master's degree and instructs an undergraduate class independently. Some universities, however, require that TFs be supervised by a professor, with whom they meet regularly and receive suggestions on ways to improve their teaching skills. TFs are paid higher salaries than TAs, and on a per-semester contract basis. In the UK, the title of "teaching fellow" is occasionally given to an academic staff member who has demonstrated excellence in lecturing.
An adjunct professor is a professor who is employed on a part-time, casual basis by a college or university and typically holds a Ph.D. As adjunct professors don't hold permanent professor jobs, they don't receive the same benefits as other academic staff, and are relieved of the research and administrative responsibilities required of full-time, permanent professors. Professors who have made teaching contributions to a department outside of their own can be recognized as adjunct professors in that department in addition to retaining their regular professor jobs, however.