A postgraduate qualification is the culmination of a program of higher education, usually undertaken at an accredited academic institution. In terms of the hierarchy of postgraduate qualifications, the highest form of this type of qualification is the doctoral degree — this is the highest qualification a person can obtain in an academic institution. The master's degree is second-highest postgraduate qualification one can achieve, and the postgraduate diploma is the least of the postgraduate qualifications. Typically, a student must complete an undergraduate degree before he or she can study for postgraduate qualifications.
There are several types of doctoral degree, for which a student must undertake an intensive level of study. These include Doctor of Philosophy, Doctor of Science and Doctor of Management. The most commonly recognizable of these is the Doctor of Philosophy (PhD or DPhil) qualification, which is awarded to students in variety of academic disciplines, from physics to psychology. PhDs are awarded to students who successfully complete an original research thesis, typically 80,000 to 100,000 words in length, in the chosen subject. Achieving a PhD is recognized globally as the highest form of academic achievement. Once an individual has completed the doctorate qualification, the honorific title — Mister, Miss, and so forth — is replaced with Doctor, regardless of the gender of the postgraduate.
A master's degree ranks second in the league table of postgraduate qualifications; recognizable master's degrees are the Master of Arts (MA), Master of Science (MS), and Master of Business Administration (MBA). Typically, it involves the completion of a number of modules, in which a student must complete a variety of assignments and exams in the chosen subject. After the modules have been completed by the student, he or she must complete a thesis, also known as a dissertation. The dissertation is similar in nature to the PhD thesis, although it is not nearly as intensive in terms of the research and thesis length required.
The postgraduate diploma is one level higher than an undergraduate degree, and it is the lowest of the postgraduate qualifications. In a typical scenario, a postgraduate diploma can be thought of as a master's degree without the final dissertation project. A student might study exactly the same modules as the master's student, but if he or she chooses not to complete the dissertation required for a master's degree, he or she will be awarded a postgraduate diploma. A student who has been awarded a postgraduate diploma might be able to undertake a dissertation project at a later date.