Academic degree
Doctoral degrees or doctorates, such as the Doctor of Philosophy degree (PhD or DPhil) or Doctor of Education (EdD or DEd) are awarded following a programme of original research that contributes new knowledge within the context of the student's discipline. Doctoral degrees usually take three years full-time. Therefore, in the UK it may only take seven years to progress from undergraduate to doctoral level – in some cases six, since having a Master's is not always a precondition for embarking on a doctoral degree. This contrasts with nine years in the United States, reflecting differences in the educational systems.
Graduate school
For the next several years the doctoral candidate primarily performs his or her research. Usually this lasts three to eight years, though a few finish more quickly, and some take substantially longer. In total, the typical doctoral degree takes between four and eight years from entering the program to completion, though this time varies depending upon the department, dissertation topic, and many other factors. For example, astronomy degrees take five to six years on average, but observational astronomy degrees take six to seven due to limiting factors of weather, while theoretical astronomy degrees take five.