A medical degree usually requires two years of coursework and laboratory sections. Understandably, this period is filled with written and oral examinations The next two years involve research projects under a professor's supervision as well as internships. At each step, professors--usually physicians and surgeons--evaluate and critique students. Comprehensive oral and written examinations occur at the end of most semesters and quarters throughout an MD program. Most schools require medical students to maintain at least a 3.0 GPA both to remain in school and to graduate.
MD programs at certain universities have unique aspects. Some, such as Howard University, offer an accelerated Bachelor of Science/Doctor of Medicine program that takes a total of six years for both degrees. Participation in this program is limited to only a few specially selected, high performing students per year. Other schools have dual MD/PhD or MD/Masters programs which last longer than the typical four year medical curriculum. However, the extra time invested may result in combinations such as MD and Masters of Public Health (MPH) or MD and PhD in Bio-genetics.
PhDs are awarded in a wide array of subjects including humanities, sciences, business, health care, and engineering. Program requirements are tailored to the nature of the subject. Students must prove something original or argue something unique to earn their degree. As a general rule, students will spend one or two years taking graduate classes and demonstrate their progress through exams, term papers and research projects. Even so, most of the degree work involves developing and proving a thesis in the form of a dissertation, or conducting research that arrives at a new scientific finding. In mathematics, a student may spend years working on an equation or focus on proofing a new mathematical idea or concept. In all cases, students meet regularly with their master professors and doctoral committees who oversee their work, give guidance and make the final decision as to whether they will be awarded a degree.
Most universities hold that teaching a subject is one of the best ways to master it. As a result graduate students are frequently required to teach lower level classes. Some PhDs, including those offered by Columbia University's biological science program, require students to teach at least two semesters in their field. In some cases, doctoral candidates oversee laboratory sections. In both science and humanities disciplines they may be called on to either assist a professor or independently teach undergraduate courses and workshops.