PhD, or Ph.D., stands for Doctor of Philosophy. A PhD is an advanced degree requiring usually three to eight years of study beyond receiving a Bachelor’s degree. The PhD candidate does not necessarily study philosophy. In fact, many candidates study science or different liberal arts fields. The title of “Doctor” is not always used, and is essentially honorary in the US. Typically, in the US, those with PhDs are not referred to as doctors as are medical doctors.

There are numerous complementary programs that involve similar years of study and take place after one has earned a bachelor’s degree. These include the D.A, or Doctor of Arts, Doctor of Education (Ed.D), the Doctor of Medicine (M.D.) and the Doctor of Law (J.D.).

PhD work in any field is quite challenging. One must usually have a clearly defined major, perform well on the Graduate Record Examinations (GRE) in both one’s specialty and in the general test, and have excellent grades, recommendations and scholastic history in order to get into a PhD program.

In most cases, those achieving a PhD in science or a liberal art will spend anywhere from one to three years studying advanced coursework in their chosen subject. Generally, time spent on coursework tends to be less if one has earned a Master’s degree first. These advanced studies may eliminate the need to take certain courses.

However, some programs are so competitive that they tend not to accept students who have not already completed a Master’s degree. Others are more likely to accept students with a Bachelor’s degree. The decision on who to accept into a PhD program is highly variable.

Most PhD candidates will either work as student teachers, lab assistants, or participate in practica while they complete their coursework. Many graduate students do at least a small amount of teaching, since many who seek a PhD do so with the goal of becoming a university professor. Some teaching may be required, and normally, the PhD student is paid a small amount, called a stipend, for teaching. This can help students afford to attend school exclusively, and usually eliminates the need for students to work outside the university.

As well as satisfying teaching or research assistant requirements, and participating in practica, most students spend a year preparing to take oral and written examinations that prove competence in their field. They then must also write a dissertation, which must be accepted and approved by the dissertation committee prior to receiving their PhD. This process can be lengthy. The dissertation must typically include original research in one’s field of expertise. The average dissertation is normally book-length.

Study in other countries is roughly similar to US standards, though slight variations exist. In general most European countries offer rigorous courses of study that are the equivalent, or more challenging than US PhD programs. Most countries accept the PhD status of those who earned their PhD elsewhere.