Thesis defense

A thesis defense, also known as "defending one's thesis," oral defense, viva voce, and various other names, is a type of final examinationfor adoctoralcandidate, and sometimes for amaster's candidate. Certain undergraduate schools, whose students are largely expected to matriculate into graduate programs, also require students to defend theses.

A thesis defense differs from a typical examination in several respects. The biggest difference is that the candidate often knows more about the topic than the examiners ("the committee," or the "jury"), having researched the topic extensively, typically over a number of years; some candidates may have devoted the better part of a decade to the work being examined. The purpose of the thesis defense is to test the candidate's knowledge of his or her subject area and thinking in related areas, and to test the candidate's knowledge of and ability to explain his or her dissertation.

The examining committee normally consists of professorsfrom theuniversity, including the candidate's primary supervisor (without whose presence the defense cannot proceed) and members of his or her advisory committee, as well as professors from other departments or faculties and, sometimes, anexternal examiner(someone not otherwise connected to the university). Each committee member will have been given a completed copy of the dissertation prior to the defense, and will come prepared to ask questions about the thesis itself and the subject matter.

Although it is always the culminating part of the assessment, the nature and real importance of the oral examination varies greatly between countries. In North Americait may take place in public or private, typically with a committee of about five (note, however, that in many schools masters thesis defenses are restricted to the examinee and the examiners, even where doctoral defenses are held in public). In theUnited Kingdom, there are only two or at most three examiners, and the examination is strictly in private, not least because there is a real chance of a candidate failing at this stage. In most countries of continentalEurope, however, the thesis defense takes place in public, with the candidate's family and friends present as well as any interested faculty, and there is no question of the candidate failing - the real assessment has taken place beforehand, in determining whether the candidate should be allowed to go forward to public examination. However even in these cases the oral examination is not only ceremonial. The performance of the candidate (and indeed of the examiners) will be discussed vigorously afterwards and will help determine their future reputation. In several countries the decision on special honours ("cum laude" in all its local variations) is also made at the defense.

The oral examination is conducted primarily in the main language of instruction. However it is generally the case that at least one of the examining board will be from another university, and in smaller countries that often means from another country, since there may be only one centre of expertise on a given topic in a country. This often means that part of the examination has to be in a common language, usually English.

Even where oral examinations take place in private, their atmosphere tends to be formal. The candidate may be asked to give a short presentation on his or her thesis, usually lasting no more than thirty minutes, after which the examiners are free to ask questions. In some countries they will proceed by seating order, with external examiners given priority. Where thesis defenses are open to the public, they are often attended by friendsorfamilyof the candidate, members of the university, especially other students in the candidate's department, and members of the community. Audience members are often permitted to ask questions when all the examiners have finished.

At some US institutions a longer public lecture (known as a "thesis talk" or "thesis seminar") by the candidate will precede the defense itself, in which case only the candidate, the examiners, and other members of the faculty may attend the actual defense.

Questions are typically about the content of the dissertation and the claims made therein. Examiners may need clarification on a point or points, or may ask the candidate to explain his or her reasoning or researchfurther. Questions are often friendly, but may also challenge the candidate's views, methods, or conclusions. Part of the evaluation is based on how well the candidate can defend his or her work.

In the UK, IrelandandHong Kongthe thesis defence is called aviva voce, (Latinfor "by live voice") examination (viva for short). Involved in the viva are two examiners and the candidate. One examiner is an academic from the candidate's own universitydepartment (not any of the candidate's supervisors) and the other is anexternal examinerfrom a different university.

In Bosnia-Herzegovina,France,Norway,Sweden,Denmark,Finland,Germany, andSwitzerlandthe oral defense is known as asoutenance: an expert in the field, often from another university, is appointed who will present the dissertation, subject it to a critical examination and discuss it with the author. In the context of the disputation, the critical examiner is termed the opponent, and the author of the dissertation the respondent. The dissertation has to be generally available in its final or at least in a preliminary published form a few weeks before the disputation (3 weeks in Sweden), which is open to the public; after the opponent is finished, anyone present is allowed to ask critical questions (anyone who does is called an "opponent ex auditorio"—an opponent from the auditorium). The final grade is decided after the disputation in a meeting between the opponent and a grading committee of three or (sometimes) four people. In theory, also the points raised by opponentes ex auditorio affect the grade. It has happened that such opponent has caused the committee not to pass the respondent, although this would be quite extraordinary nowadays.

At the end of the defense, the candidate and other persons who are not members of the jury are asked to leave the room. Alternatively, the jury leaves the room for another chamber set aside solely for this decision. The committee then deliberates and reaches a decision (normally unanimous and sometimes called a "verdict"), usually in the form of a number from one to five (this varies from school to school). Potential decisions include:

• Accepted / pass with no corrections.

The thesis is accepted as presented. A grade of some kind may be awarded, though in many countries PhDs are not graded at all, and in others only one of the theoretically possible grades (the highest) is ever used in practice.

• The thesis must be revised.

Revisions (i.e. correction of numerous grammatical or spelling errors; clarification of concepts or methodology, addition of sections) are required. One or more members of the jury and/or the thesis supervisor will make the decision on the acceptability of revisions and provide written confirmation that they have been satisfactorily completed. If, as is often the case, the needed revisions are relatively modest the examiners may all sign the thesis with the verbal understanding that the candidate will review the revised thesis with his or her supervisor before submitting the completed dissertation.

• Extensive revision required.

The thesis must be revised extensively and undergo the evaluation and defense process again from the beginning with the same examiners. Problems may include theoretical or methodological issues. A candidate who is not recommended for the degree after the second defense must normally withdraw from the program.

• Unacceptable

The thesis is unacceptable and the candidate must withdraw from the program.

This verdict is given only when the thesis requires major revisions and when the thesis defense makes it clear that the candidate is incapable of making such major revisions.

The candidate is immediately informed of the results; in the event of a successful defense the candidate's supervisor will often greet the candidate with the words, "Congratulations, Doctor X". At this moment a bottle of champagneis often produced. In some countries (e.g. France and the Netherlands), the candidate is considered to become a Doctor of Philosophy at the instant that all committee members vote in the affirmative. In others (e.g. the UK), the degree must first be conferred by the university corporation. Finally, in some countries (e.g. the USA), practice varies between universities.

The likelihood of these different verdicts varies between countries. At most US institutions the latter two verdicts are extremely unusual, since the thesis supervisor (and the other members of the jury) will normally have reviewed the thesis before the thesis defense. Such an outcome is generally regarded as a major failure not only on the part of the candidate but also by the candidate's supervisor (who should have recognized the substandard quality of the dissertation long before the defense was allowed to take place). It is also fairly rare for a thesis to be accepted without any revisions; the most common outcome of a defense is for the examiners to specify minor revisions (which the candidate typically completes in a few days or weeks).

While the decision of the examiners is normally unanimous, the official rules at most US institutions allow the doctorate to be granted with positive votes from all but one of the examiners; it is therefore possible for a candidate to pass with one negative vote. The extremely rare cases where one examiner votes against a successful candidate can have a permanent effect on the relationships among the faculty members involved.

An unsuccessful defense is extremely unlikely in countries such as the Netherlands, where the oral defense ("promotie") typically happens after the thesis has already been approved by examiners. Candidates often try for a board of opponents as large, international and prestigious as possible. All professors are required to weartogas. The oral defense is ended after a preset amount of time by the University-appointed 'pedel' orcustos who is in charge of the protocol and will end the defense with the words "Hora est!" (Latin for it is time or the hour has come). In theory, the candidate does not have to answer the questions or even be present; (s)he can relegate this to his/her assistants called "paranimfen", who also act as a formal bodyguard due to the heated nature of some academic disputes in past times. Nowadays paranimfen are often chosen from friends and family, so the practice of having them answer questions is almost completely discontinued.

On the other hand, examinations at universities on the British pattern are by no means a rubber stamp. Whilst many theses are passed with some minor corrections or revisions required by the examiners, very few are passed with no corrections whatsoever, and indeed a pass-without-correction is considered a particular honour. Moreover, it is not uncommon for British theses to be failed, as well — in which case, either major re-writes are required, followed by a new viva, or else the thesis may be awarded the lesser degree of M.Phil (Master of Philosophy) instead, preventing the candidate from resubmitting the thesis.

In the case of a successful defense, frequently many of the questions and much of the discussion will focus less on the dissertation at hand and more on further avenues of research the author might wish to explore in the future.