Despite numerous conversations with respected friends and colleagues, I can’t explain the meaning of life. I can however, discuss the meaning and purpose of a doctoral dissertation and defense—at least from my perspective. This editorial was inspired by my recent experience participating in the doctoral defense of Harald Hovland at the University Of Oslo, Norway. Let us begin with the purpose of a doctoral dissertation. My own professor, Carl Halford, would tell you that the purpose of a dissertation is to demonstrate that you can perform relatively unsupervised and self-motivated independent research that is original and significant. A quick survey of doctoral requirements from various institutions provides similar criteria and goals for the dissertation, including showing that one can contribute to the research results and research publications in a particular subject area.

Interestingly, the purpose of the dissertation defense is not as well described or defined. For example, at some institutions it serves as a test to prove that the candidate knows the research material in-depth. At other institutions the dissertation defense is simply a rite of passage at the end of a student’s research activities. In my experience, very few doctoral students in the United States fail a defense because their professors ensure that the candidates are well prepared. In Australia some schools do not require a verbal defense so instead the written dissertation is evaluated very thoroughly. For many years in the United Kingdom it was common for doctoral candidates to fail or only partially pass their defenses, and the result would determine the status under which the candidates would graduate.

As mentioned above, last month I had the opportunity to participate in the doctoral defense of Harald Hovland at the University of Oslo, Norway. I thought it might be enlightening to share some details about that experience so you can compare it with your own. Professor Sverre Holm was the committee chair, whereas Professor Jakob Stamnes and I were the two opponents. Neither of the dissertation supervisors was on the committee.

The event began with the candidate giving a presentation on a related subject that was given to him only two weeks prior to the defense. In Harald’s case, the topic was “Field Testing of Infrared Systems.” He provided an excellent presentation that lasted 45 min. No questions were allowed during or after the presentation. The committee then evaluated the presentation and provided the department with results.

The dissertation defense that followed was very formal. The department head wore a robe and led a procession with the committee members into the defense auditorium, which was filled with colleagues and family members. The candidate gave a 30-minute summary of his dissertation, “Tomographic Scanning Imagers.” Following the presentation, the two opponents were asked to come forward. I gave an evaluation of the originality and significance of the work and discussed how the dissertation was related to international research. Then I proceeded to ask challenging questions about the candidate’s research. After 10 or 15 questions, the other opponent, Professor Stamnes, came forward to begin his round. He was polished, professional, and even humorous at times, but he also came across as someone who gave the process great respect and tradition. After all questions were answered, the audience was invited to participate as well, but everyone seemed satisfied with the candidate’s eloquent defense. Finally, after a short meeting with the department head, we all proceeded back into the auditorium and congratulated Harald in front of the audience—he passed with flying colors.

By US standards, the Norwegian dissertation defense was a very formal process. Harald did an outstanding job defending his work, and it was a joy to participate in an event that was so rewarding and worthwhile for everyone involved. Harald demonstrated that he had achieved all of the goals associated with a doctoral defense—he performed independent research, contributed refereed work to three OSA journal publications, and ultimately was successful in the Norwegian rite of passage to the doctoral degree.

Ron DriggersEditor-in-Chief, Applied OpticsHarald Hovland (soon to be Dr. Hovland) and his wife, Nittaya.