Professors vs. Lecturers
Professors are scholars that are experts in their field and teachers of the highest rank. They almost always have a Ph.D., perform research in their discipline, and supervise graduate students. Professors may receive tenure (see below) and have job security after doing so. The job of a professor involves many obligations, which are usually grouped under the headings of Research, Teaching, and Service. (See here for a more detailed description of the job responsibilities of professors.) In most mathematics departments in the U.S., professors teach one or two courses per semester.Lecturers, unlike professors, are individuals hired by the university solely to teach. They usually have a Masters degree, but often do not have a Ph.D. In the mathematics department, lecturers usually teach courses prior to calculus, and a few of the freshman-level or sophom*ore-level mathematics classes. Junior-level and Senior-level mathematics courses are typically taught only by professors, and graduate courses are taught exclusively by professors. Lecturers cannot receive tenure and they often work on year-to-year contracts. Lecturers are also often paid less than professors. A lecturer will typically teach three or four courses per semester, and their job typically involves little to no research or service responsibilities. At some universities, lecturers are called "Adjunct Faculty", "Instructors", "Instructional Faculty", or even "Instructional Professors".
Tenure
After many years of accomplishment in research, teaching, and service, a professor may receive tenure. Tenure is a contractual right to a job, and essentially provides the professor with job security. A professor with tenure cannot be fired or let go from their job unless they are in violation of university rules and the university proves "just cause". Consequently, professors with tenure basically cannot be fired --- however, there is also no guarantee they will receive annual raises or other accommodations. Tenure exists to provide senior scholars with academic freedom. The idea is that if someone has proven themself through years of exemplary work and top-notch research, while simultaneously becoming an established expert in their field of study, then they have earned the right to make statements, raise questions, or do research that may be controversial or unpopular without the fear of being fired.The Path to Becoming a Professor
Graduate Students. To become a professor, one must first go to graduate school to earn a Masters degree and then a Ph.D. It typically takes 2 years to earn a Masters Degree in Mathematics and an additional 3 to 4 years to earn a Ph.D. in Mathematics.Graduate students at all levels will often run recitations for large lecture courses or work as graders or tutors for large lecture classes. Graduate students that have earned a Masters degree and are working on their Ph.D. will sometimes teach a class and be the primary instructor. Graduate school in mathematics is a very intense process with a high dropout rate. After earning a Masters degree, students must be accepted to Ph.D. candidacy in order to continue in the graduate program and earn their Ph.D. One requirement to advance to Ph.D. candidacy is to pass a set of very demanding exams known as "preliminary exams" or "qualifying exams". Not all students pass these exams, and those that do not pass all the required preliminary exams cannot enter the Ph.D. program and must leave graduate school. Others at this point may decide a Ph.D. is not for them and choose to leave graduate school for a variety of reasons. Some students who leave graduate school after earning their Masters degree may decide to become lecturers. Others may seek employment elsewhere, such as industry, government agencies, or education.Postdocs (also called Visiting Assistant Professors). Postdoctoral positions (also called postdocs) are positions that a person takes after receiving a Ph.D. with the goal of obtaining more research experience. While some teaching-focused schools or four-year colleges without a graduate program may hire a fresh Ph.D. into a tenure-track professor position, if one wants to get a job at a research university, one has to complete one or more postdoctoral positions to be qualified. Most of the time, it is expected a person will do a postdoc at a different university than the one they received their degree at to get broader experience. Postdoctoral positions typically last for 2 to 3 years, and once they end the person must find either another postdoctoral position or a tenure-track job.Usually a person completes one postdoctoral position before getting a tenure-track job as a professor, although it is not uncommon to have to do more before being able to receive a job offer. Postdocs are sometimes also called "Visiting Assitant Professors". The term "Visiting" is meant to indicate the position is not permanent and not tenure-track, and their contract will end in a few years.
Professors. Professors are tenure-track or tenured faculty. In the United States there are three ranks of professor: Assistant Professor, Associate Professor, and Full Professor. (In other countries the rankings may be different, and sometimes similar terms in other countries have different meanings.)
- Assistant Professors. An Assistant Professor is a beginning-level professor. Assistant Professors are also called "tenure-track professors", and a college or university hires them with the hopes that they will earn tenure. An Assistant Professor usually has a six-year contract, and in the fifth year they apply for tenure. The tenure application process typically takes a year, and during this time the Assistant Professor is reviewed extensively. If the Assistant Professor passes the review, they receive tenure (see above) and are promoted to the rank of Associate Professor. If they do not pass, they are fired and have to leave the university within a year. Promotion from Assistant Professor to Associate Professor typically includes not only tenure, but also an increase in pay, greater responsibilities, and more respect.
- Associate Professors. An Associate Professor is a mid-level professor. Associate Professors continue their responsibilities as a professor, with the goal of expanding their research and building their body of work. After approximately 6 years, Associate Professors have the option of applying for promotion to Full Professor. The requirements for promotion typically include that the Associate Professor's work has grown substantially since the time they were promoted to Associate Professor, to the point that they have an international reputation among their colleagues and their research has significant impact within their field of study. Unlike the situation for Assistant Professors, an Associate Professor is not required to apply for promotion to Full Professor, and if they do apply but the promotion is not awarded, there is essentially no change in their position and they are allowed to keep their job. Also, unlike an Assistant Professor's application for tenure and promotion, if an Associate Professor applies for promotion to Full Professor and the promotion is not awarded, they are allowed to apply again in the future. As with the application for tenure, the application for promotion from Associate Professor to Full Professor is a long process, typically taking a year and involving an in-depth review. Associate Professors who are promoted to Full Professors typically receive an increase in pay, greater responsibilities, and more respect. Not all Associate Professors will apply for promotion or receive promotion to Full Professor, and many people may stay at the rank of Associate Professor all their life.
- Full Professors. A Full Professor is a senior-level professor. Full Professors continue their responsibilities as a professor, with the goal of expanding their research and building their body of work even further. Full Professors also often take a leadership role in the department, and may be involved in important departmental and extra-departmental administrative tasks. Full Professor is the highest rank that a professor can achieve and is seldom achieved before a person reaches their mid-40s. There are, however, additional honorary titles or positions, that a Full Professor may be granted. These are often called "Distinguished Professors", "Named Professors", or "Chaired Professors" (not to be confused with the position of Department Chair, which is an administrative position). Full professors with a Distinguished Professorship often receive additional salary, greater prestige, more perks, and their teaching load may be reduced (sometimes to zero classes) so that they can focus more on their research.
What does this mean for you as a student?
In the United States, the term "Professor" can be confusing because it is used to mean three very different things:- Anyone who teaches a college class.
- A tenured or tenure-track faculty member who is at the rank of Assistant Professor, Associate Professor, or Full Professor.
- A faculty member at the rank of Full Professor.
When you address the person teaching your classes, it is probably best if you refer to them "Professor So-and-So", even if you do not know their exact position. This has the least chance of being offensive or insulting. You should never call your instructors by the title "Mr. or Ms.". Always use the title "Professor" or "Dr.".
If you need letters of recommendation or academic advice (e.g., what classes you should take, whether you should consider going to graduate school and how to prepare), it is better that you talk to a faculty member who is an Assistant, Associate, or Full Professor rather than a Lecturer, Graduate Student, or Postdoc.
If you do not know the position or rank of the person teaching your class, you can find out on your mathematics department's website. Almost every professor will list their rank on their website, and it will also be listed in their Curriculum Vitae (CV).
