Main positions

• Assistant professor: the entry-level position, for which one usually needs a Ph.D. or other doctorate; a master’s degree may suffice, especially at community colleges or in fields for which there is a terminal master’s degree. In some areas, such as the natural sciences, it is uncommon to grant assistant professor positions to recently graduated Ph.D.s, and nearly all assistant professors will have completed some time as post doctoral fellows. 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-anywhere from 3 to 7 years. Rates for achieving tenure vary, depending on the institutions and areas of study; in most places at least 50% of assistant professors are tenured and promoted to associate professors after the sixth year; however, this number can be as low as 10% in natural sciences departments of top universities, or over 70% in non-Ph.D. granting schools. In unusual circumstances, it is possible to receive tenure but to remain as an assistant professor, typically when tenure is awarded early. Traditionally, in an effort to diversify the academic pool, universities prefer to hire those who have graduated from a different university and not someone who may be a former student. This remains true for all levels.
• Associate professor: the mid-level position, usually awarded (in the humanities and social sciences) after a substantial publication record, such as a book, book contract, or second book–although the requirements vary considerably between institutions and departments. Generally upon obtaining tenure, one is also promoted to associate professor. Less commonly, a person may be hired at the associate professor level without tenure. Typically this is done as a financial inducement to attract someone.from outside the institution, but who might not yet meet all the qualifications for tenure. If awarded to a non-tenured person, the position is usually tenure-track with an expectation that the person will soon qualify for tenure. However, at some institutions (including Harvard), associate professors are untenured and only rarely promoted to tenure.
• (Full) professor: the senior position. In a traditional school this position is always tenured. However, this may not be the case in a for-profit private institution. The absence of a mandatory retirement age contributes to “graying” of this occupation. The median age of American full professors is currently around 55 years. Very few people attain this position before the age of 40. The annual salary of full professors averages around $95,000, although less so at non-doctoral institutions, and more so at private doctoral institutions (not including side income from grants and consulting, which can be substantial in some fields); in addition, institutions in major cities or high cost of living areas will pay higher salaries. Full professors earn on average about 70% more than assistant professors in the same institution. However, particularly in scientific and technical fields, this is still considerably less than salaries of those with comparable training and experience working in industry positions.

Life of a typical natural sciences professor in the United States:

• Bachelor’s degree: age 18-22
• Ph.D.: 22-30 (typically takes between five and eight years)
• Post-doc: 30-33 (highly variable, and multiple post-docs are increasingly common)
• Assistant professor: 33-38
• Associate professor: 38-45 (varies)
• Full professor: 45-70 (professors were forced to retire at 70 during 1986-1993, this is no longer the case; retirement age is now at professors’ own discretion; most retire between 65 and 75)
• Professor emeritus: 70+