Working on a doctorate requires time, motivation, dedication and a passion for intellectual growth.
Working on a doctorate requires time, motivation, dedication and a passion for intellectual growth.

Becoming a doctor of philosophy, or Ph.D., is no easy feat, and it's not for those who have limited time or motivation. Depending on which school a student attends and the chosen discipline, earning a doctorate can be quite time consuming. The credit-hour requirements for a doctoral degree may differ slightly from institution to institution, but in general, they're composed of the same categories of courses. Students must complete field of concentration credit hours, research credit hours and credit hours devoted to the completion of a dissertation.

Total Credit Hours

Schools operate on either the quarter system or the semester system, which require different numbers of total credit hours for a degree. Though there can be some variation, a school may require 96 quarter hours or 64 semester hours to complete a doctoral program. A conversion ratio of two semester hours to three quarter hours can be used to compare the total number of credit hours. For instance, a student who has earned 24 semester hours will have accumulated an equivalent of 36 quarter hours. This conversion process is only relevant if a student transfers credit into a doctoral program -- for example, from a master's degree program.

Credit Hours for Concentration

The doctor of philosophy title represents a degree, but does not reveal the area of concentration. For instance, a student may pursue a doctorate in economics, English literature, history of western civilization or educational leadership. The area of concentration is the chief area of graduate study and usually includes a requirement of about 48 semester hours. Although the requirement of concentration hours varies among institutions, the majority of the doctoral program's credit hours fall into this category. However, unlike the undergraduate core curriculum, virtually all credit hours in the program are at least indirectly related to the student's discipline.

Credit Hours for Research Methods

The vast majority of doctoral programs focus on research and require quantitative and qualitative research methods courses, in addition to courses on research design. Again, the number of hours required varies across institutions, but 24 semester hours of research coursework is typical. Additionally, programs may require practical evidence that students can perform quantitative and qualitative research. This may take place as part of the research courses, in which projects can provide evidence of proficiency, or through the more in-depth work required to complete the dissertation.

Credit Hours for the Dissertation

The culminating and most difficult part of a doctoral program is completing the dissertation. Though the requirement for dissertation credit hours may vary slightly, Mercer University requires 12 quarter hours for the dissertation work, which corresponds to 18 semester hours. During these courses, students conduct the majority of their dissertation-writing. In general, students also spend a portion of the first two or three years in a doctoral program selecting a research topic, determining appropriate research design and beginning the proposal process.