Planning a PhD Dissertation: Advice to Research Students

In their Memorandum to Graduate Students (1998) the Board of Graduate Studies define the requirement of a PhD Dissertation in the following statement in paragraph 9:

"Before recommending the award of the PhD Degree the Examiners shall satisfy themselves that the dissertation is clearly written, that it takes due account of previously published work on the subject, and that it represents a significant contribution to learning, for example through the discovery of new knowledge, the connection of previously unrelated facts, the development of new theory, or the revision of older views. Examiners are asked to bear in mind that the subject of a PhD Candidate's research is approved in the light of what it is reasonable to expect a student to complete within three years full-time research."

In Engineering this statement might well be extended to include the development of new instruments, experimental methods and computational techniques. As well as describing the original contributions of the candidate the dissertation must demonstrate that he or she has:

a) Developed the experimental, mathematical and computational skills appropriate to a professional research worker in the chosen field.

b) Acquired a good general understanding of previous and contemporary research in the field through the reading of books and published papers.

c) Learnt how to distinguish the important from the trivial, both in his or her own work and in the work of others.

d) Developed the ability to organise material logically and present it in clear, precise and grammatical English.


The prime function of a PhD dissertation is to enable the Examiners to judge whether a candidate meets the requirements for the degree. A dissertation is, however, sometimes given another function by a student - that of providing a permanent and complete record of the student';s work in the Department. (For example, experimental apparatus and computer programs are often described in great detail - detail which may be extremely useful to later research students.) This second function must always be kept subordinate to the principal one of providing material on which to assess the candidate. It is clearly important for a research student to keep careful working records and be concerned about building up the general store of knowledge and expertise within the Department.

However, details which are worth preserving for later users of apparatus or computer programs are not necessarily of interest to Examiners. Indeed the inclusion of too much detail in a dissertation may cause the Examiner to doubt whether the candidate had really learnt how to distinguish the important from the trivial. Such details can always be preserved for posterity in separate documents such as Departmental reports.


PhD dissertations commonly follow the sequence:

Statement of the problem and the reason for solving it.

Review of previous work in the field.

Development of the candidate's own ideas, backed up by experimental evidence and/or mathematical analysis.

Discussion of the impact that the contributions are likely to have on future Engineering practice.
Suggestions for further research.

Appendices.

There will normally be a preface and table of contents, in addition to the summary required by Regulations.

A numbered list of references should be included either as a single list at the end of the dissertation or by chapter. When a reference is quoted in the text both the name of the author(s) and the number of the reference should be included.

It is both convenient and conventional to organise the information into a hierarchical structure which provides clear classification of the information into Parts, Chapters, Sections, Sub-sections, etc.

Information of secondary importance (and information whose inclusion would break the flow of the text) is placed in Appendices and Annexes.

The information presented by diagrams, photographs and tables should be carefully integrated with text, although physically they may be placed at the end of the dissertation. Broadly two classes of diagram may be distinguished: graphs or scale drawings to convey quantitative information and sketches designed to clarify arguments. The clearest and most appropriate presentation of information should aimed for and it is, therefore, normally a mistake to have a large number of curves on one graph unless it is essential for comparative purposes. Sketches should be clear and well labelled, and it may be advantageous to display them within the text. Photographs should only be included if they make points which cannot be made better by other means.

It is important to emphasise the requirements of the Board of Graduate Studies that the dissertation should be clearly written. The argument should flow from one thought to the next, and the right logical order is not necessarily the same as the order in which ideas developed historically. It should be ensured that words are interpreted with their intended meaning and the guidance of Gowers ' The Complete Plain Words' is strongly recommended.


Some Points of detail

If the evidence is experimental, then the apparatus and techniques should be described in such a manner so as to convince a reader of the dissertation that the experiments were well planned and are reliable. There should be sufficient detail to enable another experimentalist to repeat the experiments and observe the same results.

Similarly, if the evidence or argument refer to a substantial computer program, then the program should be described in a manner and with sufficient depth to convince a reader that it well conceived and the results are reliable within the limitation of the program. These limitations should be clearly explained.

Again, if the argument is mathematical, then it must be pertinent to the main themes. Theory should be described in such a way as to convince a reader that the results follow logically from plausible premises. The argument should be comprehensible without entering into trivial detail. Where tedious algebra has to be included it can often be placed in an appendix. Standard symbols should be used where possible.


The dissertation should not contain:

A summary of all the work done by the candidate during his or her research years, unless all of these activities were directly relevant to the dissertation.

Information which merely demonstrates that the candidate comprehends a piece of knowledge but has little to do with his or her contributions.
Trivial details, such as routine calculations, irrelevant data, and descriptions of standard experimental techniques.

The complete listing of computer programs unless it is essential for clear presentation.

S.I. Units should be used in dissertations unless it is the accepted practice in the Department to use other units for particular quantities.

Dissertations should include a page giving a list of key words. This is to help with compilation of the Library';s subject card index, and the Librarian Mrs McOwat, is always prepared to give advice on the preparation of the lists.

Candidates are required to submit two copies of their dissertation which will not be returned. After the award of the degree one copy will be placed in the University Library and the other copy will be placed in the Department Library.

The Department offers certain facilities for reproducing and binding dissertations and it makes a contribution towards the cost. Details of these arrangements should be obtained from Mrs McOwat just before you start to prepare your dissertation.


The length of a PhD dissertation

The limit in length of a PhD dissertation is 65,000 words including appendices, bibliography, footnotes, tables and equations. The limit on the number of figures is 150. The word limit corresponds to 250 A4 pages of double-spaced normal size type and 260 words to the page. Typically, dissertations contain about 55,000 words but some of the best dissertations are much shorter than this. Permission to exceed the limits of 65,000 words or 150 figures is only granted by the Degree Committee in exceptional circumstances.
A candidate who at the planning stage of the dissertation believes that either limit may be exceeded, should consult both the Supervisor and the Secretary of the Degree Committee. Each candidate must submit with the dissertation a statement signed by the candidate giving the length of the dissertation and the number of figures. Any dissertation which, without the prior permission of the Degree Committee, exceeds the permitted limits will be referred back to the candidate for revision before being forwarded to the examiners.

Note that candidates may apply to the Degree Committee for permission to include additional material on media such as CDs or DVDs, as long as it is packaged with the dissertation. This material is not normally subject to the length constraints given above. However this additional material should not form an integral part of the connected arguments presented inthe thesis and the Examiners may choose to ignore such material.


Typing and printing of dissertations

Candidates who plan to submit a typed dissertation should select a type font that produces clear script of adequate size. The quality of presentation will normally be improved by using a word processing system such as, for example, LaTeX. The text must be clear and of a size that is easy to read. As a guide, LaTeX 12 pt report style or its equivalent, giving about 12 words per line and 45 lines per page would be suitable. It is permissible for dissertations to be printed on both sides of the page using one and a half spaced typing. The Board of Graduate Studies accept dissertations in either A4 or A5 format.

Candidates may wish to discuss the choice of format with their Supervisor beforehand.


Acknowledgements

Regulation 7 of the regulations for graduate students states that ';a student, in submitting a dissertation, shall state, generally in a preface and specifically in notes or in a bibliography, the sources from which his or her information is derived, the extent to which he or she has availed himself or herself of the work of others, and the portions of his or her dissertation which he or she claims as his or her own original work.'

Examiners pay particular attention to this regulation. A candidate should discuss the matter fully with his or her supervisor during the writing of the dissertation, and should consult the Secretary of the Degree Committee if difficulties arise.


Dates of submission of dissertation and oral examination

Candidates are reminded that in paragraph 27 of the Memorandum to Graduate Students (1998) they are warned to allow at least eight weeks after the submission of their dissertation for the examiners to arrange the oral examination.