The dissertation or thesis is written on an original topic of research. In most institutions it is the major portion of work after completion of two to three years of classes. It could take years to complete as a full-time student. The original topic and supporting documentation is typically presented to a thesis committee, who advise the student, make recommendations etc. This individuals are in addition to the students mentor. Lastly, the student must defend the dissertation, to the satisfaction of a final committee. If the dissertation is accepted, the student is then awarded the doctoral degree.