Professor

A professor is a senior teacher, lecturer and researcher, usually in a college or university. Professors are qualified experts who give lectures and seminars in their field of study, such as the basic fields of science or literature or the applied fields of engineering, medicine, law, or business. They also perform advanced research in their fields and are expected to do pro bono community service (including consulting functions, such as advising government and not-for-profit entities) and train young academics who should replace them. The balance of these four classic fields of professorial tasks depends heavily on the institution, place (country), and time. For example, professors at highly research-oriented universities in the U.S. (and all European universities) are promoted primarily on the basis of their research achievements.

Differences

The basic difference between levels of professor according to the national academic system is that in the English-speaking countries, the designation is based on career, whereas in Continental Europe, it is based on position. That means that if a North American Assistant Professor is performing particularly well, he or she can be promoted to Associate Professor, and if this is the case again, on to (full) Professor (in the United Kingdom and other countries the ranks are different, but the same principle applies). In the Continental European system, the different fields and sub-fields of teaching and research are allotted certain (professorial) chairs, and one can only become a professor if one is appointed to such a chair (which then has to be free, i.e., unoccupied, of course). Therefore, the different professorial ranks are not necessarily comparable.

Differences may be distinctive in two main groups, "teaching professors" and "research professors" for the same body of knowledge in schools and colleges. There are also "corporate professors" in the work place. A student/professional, say in accounting may have to learn through different expertises to be qualified as expert.

Tenure

A key concept is that of tenure. A professor who holds tenure is virtually undismissable and appointed for life. In theory, professors are free to hold and advance controversial views, as the faculty generally insists on academic freedom. Tenure was thus introduced to preserve academic autonomy and integrity, i.e. the professor was supposed to be kept out of current political or other controversies of the public because it was recognized that this was beneficial for state, society, and academe in the long run. Tenure has recently become under attack by those who want a more business-like approach to universities, including performance review, audits, performance-based salaries, etc.

Survey of the main systems and concepts

North American

Main positions

assistant professor: the entry-level position, for which one usually needs a Ph.D., sometimes only a masters degree (at some schools/colleges and exceptions* such as Clinical Professorship). In some areas, such as the natural sciences, it is uncommon to grant assistant professor positions to freshly graduated Ph.D.s, and nearly all assistant professors have to spend some time as post-docs. The position is generally not tenured, although in most institutions, the term is used for "tenure-track" positions; that is, the candidate can become tenured after a probationary period - usually 5-7 years. When this is the case, tenure rates vary greatly, depending on the institutions and areas of study; in some places as many as 90% of assistant professors are ultimately denied tenure, whereas the remaining 10% are tenured and promoted to associate professors ( however, tenure rates of 50% or higher are more common ). Strictly speaking, the position is related to a pay grade rather than to tenure status, so in unusual circumstances it is possible to receive tenure but to remain in the assistant professor pay grade.
associate professor: the mid-level position, usually awarded (in the humanities and social sciences) after the "second book" — although the requirements vary considerably between institutions and departments. Can be tenured or not, however, usually upon obtaining tenure one is promoted to associate professor. In most institutions, the position is tenured, however strictly speaking the position is related to a pay differential and can be awarded to non-tenured persons. If awarded to a non-tenured person, the position is generally tenure-track.
(full) professor: the senior position. In a traditional school this is always tenured. However, this may not be the case in a for-profit private institution. Length of tenure track and absence of mandatory retirement age contribute to "graying" of this occupation. Median age of American full professors is currently around 55 years. Very few people attain this position before the age of 40. This position is well paid - full professors are likely to earn about 50% more than assistant professors in the same university. However, particularly in scientific and technical fields, professors typically earn considerably less than those with comparable training and experience working in industry positions.

distinguished professor, distinguished teaching professor, distinguished research professor, University Professor, Institute Professor: these titles, often specific to one institution, generally are granted to the top few percent of the tenured faculty (and sometimes to under one percent).

Other positions:

professor emeritus: after full professors retire from active duties, they may continue to teach and to be listed; they may also draw a very large percentage of their last salary as pension (as tenure is technically for life). NB: The concept has in some places been watered down to include also associate tenured professors; in some systems and institutions, it needs a special act or vote.
visiting professor: someone visiting another college or university to teach for a limited time; this may be someone who is a professor elsewhere or a distinguished scholar or practitioner who is not. The term may also refer simply to terminal (usually 1-3 years) teaching appointments and/or post-doctorate research appointments (which are much like research internships).
adjunct professor: someone who does not have a permanent position at the academic institution; this may be someone with a job outside the academic institution teaching courses in a specialized field; or it may refer to persons hired to teach courses on contractual basis (frequently renewable contracts); it is generally a part-time position, although the number of courses taught can vary from a single course to a full-time load (or even an overload); these positions are generally not obligated to participate in administrative responsibilities at the institution often expected of other full-time professors. The pay for these positions is generally very poor, especially considering that most adjuncts have a PhD. In other cases, an adjunct may hold one of the standard ranks in another department, and be recognized with adjunct rank for making significant contributions to the department in question.
named chair: a particularly senior full professor who is awarded a specific, endowed chair that has been sponsored by a fund, firm, person, etc. Named chairs are usually similar to the Continental European model in that they are a position rather than a career rank.
professor by courtesy: a professor who is primarily and originally associated with one academic department, but has become officially associated with a second department, institute, or program within the university and has assumed a professor's duty in that second department as well. Example: "Henry T. Greely is Professor of Law and Professor, by courtesy, of Genetics at Stanford University". Usually the second courtesy appointment carries with it fewer responsibilities and fewer benefits than a single full appointment.
professor - research: a professor who does not take on all four of the classic duties (see overview) but instead focuses on research. Typically, such a professor may be invaluable to his university department in procuring research funding and/or in publishing scholarly works, and therefore the department would prefer that he not distract himself with teaching duties that are not directly linked to his research activities. Usually research professors must fund their salary entirely or largely through research grants.
- By analogy with the above, one often sees assistant or associate research professors, and assistant or associate — but seldom if ever full — teaching professors who focus on teaching and supervising teaching assistants.
Honorary professor: normally granted to those who with significant contribution to the school and community. Say, by donation for furtherance of research and academic development.
Gypsy scholar: is an informal term given to some academics who either move several times between institutions and/or work at two or more institutions at a time. There are several possible reasons explaining the existence of gypsy scholars, among these are the fact that many teaching jobs are now either part-time or terminal (1-3 years), with tenure-track positions harder to secure, and also a high cost of housing and living. The latter appears to have become a fairly common situation in California, where the price of housing has skyrocketed (as of 2005).

In practice, students at many North American universities will both due to habit and out of courtesy refer to any instructor as a "professor" regardless of status, including those holding adjunct or term-limited appointments; exceptions are usually only made in the case of graduate students or visiting artists, etc, as the students are more concious of their less senior status, or those who have requested not to be addressed as "Professor".

Most other English-speaking countries

See Lecturer and academic rank for an explanation of these titles

In Britain and some Commonwealth countries (but not Canada, which follows the North American system), equivalently senior academics to assistant and associate professors are generally known as "Lecturers", "Senior Lecturers" and "Readers", with professorships reserved for only the most senior academic staff. A Professor in these countries holds either a departmental chair (generally as the head of the department or of a sub-department) or a personal chair (a professorship awarded specifically to that individual). In that sense, only full professors (North American style) are equivalents of professors. The title of "Professor" is a great honour, normally reserved in correspondance to full professors only; lecturers and readers are properly addressed by their academic qualification (Dr for a Ph.D. or M.D. and Mr otherwise). However, if one is unsure of the rank, it never hurts to inflate it in direct address.

French (France, Belgium)

After the doctorate or a grande école, scholars who wish to enter academe may apply for a position of maître de conférences ("master of conferences").

After some years in this position, they may take an "habilitation to direct theses" before applying for a position of professeur des universités ("university professor"). In the past, this required a higher doctorate. In some disciplines such as Law and Economics, candidates take the agrégation examination.

German (Central European)

After the doctorate, German scholars who wish to go into academe are supposed to take a Habilitation, i.e. they write a second thesis and spend some time in an inferior position. Once they pass, they are called Privatdozent and are eligible for a call to a chair.

Note that in Germany, there has been always a debate of whether Professor is a title that remains one's own for life once conferred (similar to the doctorate, which becomes part of the legal name), or whether it is linked to a function (or even the designation of a function) and ceases to belong to the holder once she or he quits or retires (except in the usual case of becoming Professor emeritus). The former view has won the day and is by now both the law and majority opinion.

When appropriate the joint title "Professor Doctor" has also been heard in the German system.

Similar or identical systems as in Germany (where a Habilitation is required) are in place e.g. in Austria, the German-speaking part of Switzerland, Poland, the Czech Republic, Slovakia, Hungary and Slovenia.

Main positions:

professor ordinarius (ordentlicher Professor, o. Prof.): professor with chair, representing the area in question. In Germany, it's common to call these positions in colloquial use "C4" professorships, due to the name of respective entry in the official salary table for Beamte. (Since the recent reform of the salary system at universities, you might now find the denomination "W3 professor".)
professor extraordinarius (außerordentlicher Professor, ao. Prof.): professor without chair, often in a side-area, or being subordinated to a professor with chair. Often, successful but junior researchers will first get a position as ao. Prof. and then later try to find an employment as o. Prof. at another university. Colloquially called a "C3 professor" in Germany (or in the new scheme: "W2")
professor emeritus: just like in Northern America (see above); used both for the ordinarius and for the extraordinarius, although strictly speaking only the former is entitled to be called this way. Although retired and being payed a pension instead of a salary, they may still teach and take exams and often still have an office
Juniorprofessor: an institution started in 2003 in Germany, this is a 6-year time-limited professorship for promising young scholars without Habilitation. It is supposed to rejuvenate the professorship through fast-track for the best, who eventually are supposed to become professor ordinarius. This institution has been introduced as a replacement for the Habilitation, which is now considered more an obstacle than a quality control by many. Being new, the concept is highly debated due to the lack of experiences. The main point of criticism is that the Juniorprofessor is expected to apply for professorships at other universities during the later of the six years, as his university is not supposed to offer him tenure itself (other than in the tenure track schemes used e.g. in the USA).

Other positions:

Honorarprofessor: equivalent of the North American adjunct professor, non-salaried.
außerplanmäßiger (apl.) Professor: either a tenured university lecturer or Privatdozent to whom the title is given if she or he has not attained a regular professorship after a while, or likewise an adjunct professor. The word außerplanmäßig (meaning "outside of the plan (of positions and salaries)") denotes that he is not paid as a professor but only as a researcher.

Other professors:

In the United States, the bestowal of titles on persons is prohibited by constitution. On the other hand, most European governments actively grant different honorifics to their noted citizens. Therefore, the government is actually considered to have a final say in who should be called a professor. This leads to some other uses of professor.

Professor as a honorary title: In some countries using the German-style academic system (e.g. Austria, Finland, Sweden), Professor is also an honorific title that can be bestowed upon an artist, scholar, etc., by the President or by the government, completely independent from any actual academic assignment.
Professor as a title for a job outside the academia: In some countries, the directors of governmental research institutes or laboratories may automatically or semi-automatically receive the professor's designation. Usually these positions require scientific background qualifying a person for a university chair.
Gymnasialprofessor (High School Professor): Senior teachers at certain senior high schools in some German states and in Austria were also designated Professor in the late 19th and early 20th century.
Fachhochschulprofessor: professors at a Fachhochschule, which are less paid and don't hold the Habilitation. As they are generally called simply Professor, since the 1970s, professors of any kind that are actually affiliated with a university may call themselves University Professor.

Israel

The rank system largely parallels the American one, except that there are four faculty ranks rather than three: lecturer (martze), senior lecturer (martze bakhir), associate professor (profesor khaver), and full professor (profesor min ha-minyan). The most junior rank is presently in the process of being phased out: depending on the institution, a candidate is considered for tenure together with promotion to senior lecturer or to associate professor.

Professors in fiction

In fiction, in accordance with a stereotype, professors are often depicted as being shy and absent-minded. An obvious example is the 1961 movie The Absent-Minded Professor. Professors have also been portrayed as being misguided, such as the one who helped the villain Blofeld in the James Bond film Diamonds Are Forever, or simply evil like the Professor Moriarty who fought Sherlock Holmes. See also: mad scientist.

Quote

"Lectures," said McCrimmon, "are our most flexible art form. Any idea, however slight, can be expanded to fill fifty-five minutes; any idea, however great, can be condensed to that time. And if no ideas are available, there can always be discussion. Discussion is the vacuum that fills a vacuum. If no one comes to your lectures or seminars, you can have a workshop and get colleagues involved. They have to come, and your reputation as an adequately popular teacher is saved."

(John Kenneth Galbraith, A Tenured Professor)