How to Write a PhD Thesis 1

How to Write a PhD Thesis
How many copies?
Talk to your adviser about this. As well as those for the examiners, the university libraries and
yourself, you should make some distribution copies. These copies should be sent to other
researchers who are working in your field so that:
m they can discover what marvellous work you have been doing before it appears in
journals;
m they can look up the fine details of methods and results that will or have been published
more briefly elsewhere;
m they can realise what an excellent researcher you are. This realisation could be useful if a
post- doctoral position were available in their labs. soon after your submission, or if they
were reviewers of your research/post-doctoral proposal. Even having your name in their
bookcases might be an advantage.
Whatever the University's policy on single or double-sided copies, the distribution copies could
be double-sided so that forests and postage accounts are not excessively depleted by the exercise.
Your adviser could help you to make up a list of interested and/or potentially useful people for
such a mailing list. Your adviser might also help by funding the copies and postage if they are
not covered by your scholarship.
The following comment comes from Marilyn Ball of the Australian National University in
Canberra: "When I finished writing my thesis, a postdoc wisely told me to give a copy to my
parents. I would never have thought of doing that as I just couldn't imagine what they would do
with it. I'm very glad to have taken that advice as my parents really appreciated receiving a copy
and proudly displayed it for years. (My mother never finished high school and my father worked
with trucks - he fixed 'em, built 'em, drove 'em, sold 'em and junked 'em. Nevertheless, they
enjoyed having a copy of my thesis.)"
Personal
In the ideal situation, you will be able to spend a large part---perhaps a majority---of your time
writing your thesis. This may be bad for your physical and mental health.
Typing
Set up your chair and computer properly. The Health Service, professional keyboard
users or perhaps even the school safety officer will be able to supply charts showing
recommended relative heights, healthy postures and also exercises that you should do if
you spend a lot of time at the keyboard. These last are worthwhile insurance: you do not
want the extra hassle of back or neck pain. Try to intersperse long sessions of typing with
other tasks, such as reading, drawing, calculating, thinking or doing research.
If you do not touch type, you should learn to do so for the sake of your neck as well as for
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How to Write a PhD Thesis
productivity. There are several good software packages that teach touch typing
interactively. If you use one for say 30 minutes a day for a couple of weeks, you will be
able to touch type. By the time you finish the thesis, you will be able to touch type
quickly and accurately and your six hour investment will have paid for itself. Be careful
not to use the typing exercises as a displacement activity.
Exercise
Do not give up exercise for the interim. Lack of exercise makes you feel bad, and you do
not need anything else making you feel bad while writing a thesis. 30-60 minutes of
exercise per day is probably not time lost from your thesis: I find that if I do not get
regular exercise, I sleep less soundly and longer. How about walking to work and home
again? (Walk part of the way if your home is distant.) Many people opine that a walk
helps them think, or clears the head. You may find that an occasional stroll improves your
productivity.
Food
Do not forget to eat, and make an effort to eat healthy food. You should not lose fitness or
risk illness at this critical time. Exercise is good for keeping you appetite at a healthy
level. I know that you have little time for cooking, but keep a supply of fresh fruit,
vegetables and bread. It takes less time to make a sandwich than to go to the local fast
food outlet, and you will feel better afterwards.
Drugs
Thesis writers have a long tradition of using coffee as a stimulant and alcohol or
marijuana as relaxants. (Use of alcohol and coffee is legal, use of marijuana is not.) Used
in moderation, they do not seem to have ill effects on the quality of thesis produced.
Excesses, however, are obviously counter-productive: several expressi and you will be
buzzing too much to sit down and work; several drinks at night will slow you down next
day.
Others
Other people will be sympathetic, but do not take them for granted. Spouses, lovers,
family and friends should not be undervalued. Spend some time with them and, when you
do, have a good time. Do not spend your time together complaining about your thesis:
they already resent the thesis because it is keeping you away from them. If you can find
another student writing a thesis, then you may find it therapeutic to complain to each
other about advisers and difficulties. S/he need not be in the same discipline as you are.
Coda
Keep going---you're nearly there! Most PhDs will admit that there were times when we thought
about reasons for not finishing. But it would be crazy to give up at the writing stage, after years
of work on the research, and it would be something to regret for a long time.
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How to Write a PhD Thesis
Writing a thesis is tough work. One anonymous post doctoral researcher told me: "You should
tell everyone that it's going to be unpleasant, that it will mess up their lives, that they will have to
give up their friends and their social lives for a while. It's a tough period for almost every
student." She's right: it is certainly hard work, it will be probably be stressful and you will have
to adapt your rhythm to it. It is also an important rite of passage and the satisfaction you will feel
afterwards is wonderful. On behalf of scholars everywhere, I wish you good luck!
A suggested thesis structure
The list of contents and chapter headings below is appropriate for some theses. In some cases,
one or two of them may be irrelevant. Results and Discussion are usually combined in several
chapters of a thesis. Think about the plan of chapters and decide what is best to report your
work. Then make a list, in point form, of what will go in each chapter. Try to make this rather
detailed, so that you end up with a list of points that corresponds to subsections or even to the
paragraphs of your thesis. At this stage, think hard about the logic of the presentation: within
chapters, it is often possible to present the ideas in different order, and not all arrangements will
be equally easy to follow. If you make a plan of each chapter and section before you sit down to
write, the result will probably be clearer and easier to read. It will also be easier to write.
Copyright waiver
Your institution may have a form for this (UNSW does). In any case, this standard page
gives the university library the right to publish the work, possibly by microfilm or some
other medium. (At UNSW, the Postgraduate Student Office will give you a thesis pack
with various guide-lines and rules about thesis format. Make sure that you consult that for
its formal requirements, as well as this rather informal guide.)
Declaration
Check the wording required by your institution, and whether there is a standard form.
Many universities require something like: "I hereby declare that this submission is my
own work and that, to the best of my knowledge and belief, it contains no material
previously published or written by another person nor material which to a substantial
extent has been accepted for the award of any other degree or diploma of the university or
other institute of higher learning, except where due acknowledgement has been made in
the text. (signature/name/date)"
Title page
This may vary among institutions, but as an example: Title/author/"A thesis submitted for
the degree of Doctor of Philosophy in the Faculty of Science/The University of New
South Wales"/date.
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Abstract
Of all your thesis, this part will be the most widely published and most read because it
will be published in Dissertation Abstracts International. It is best written towards the
end, but not at the very last minute because you will probably need several drafts. It
should be a distillation of the thesis: a concise de***ion of the problem(s) addressed,
your method of solving it/them, your results and conclusions. An abstract must be selfcontained.
Usually they do not contain references. When a reference is necessary, its
details should be included in the text of the abstract. Check the word limit.
Acknowledgements
Most thesis authors put in a page of thanks to those who have helped them in matters
scientific, and also indirectly by providing such essentials as food, education, genes,
money, help, advice, friendship etc. If any of your work is collaborative, you should make
it quite clear who did which sections.
Table of contents
The introduction starts on page 1, the earlier pages should have roman numerals. It helps
to have the subheadings of each chapter, as well as the chapter titles. Remember that the
thesis may be used as a reference in the lab, so it helps to be able to find things easily.
Introduction
What is the topic and why is it important? State the problem(s) as simply as you can.
Remember that you have been working on this project for a few years, so you will be
very close to it. Try to step back mentally and take a broader view of the problem. How
does it fit into the broader world of your discipline?
Especially in the introduction, do not overestimate the reader's familiarity with your topic.
You are writing for researchers in the general area, but not all of them need be specialists
in your particular topic. It may help to imagine such a person---think of some researcher
whom you might have met at a conference for your subject, but who was working in a
different area. S/he is intelligent, has the same general background, but knows little of the
literature or tricks that apply to your particular topic.
The introduction should be interesting. If you bore the reader here, then you are unlikely
to revive his/her interest in the materials and methods section. For the first paragraph or
two, tradition permits prose that is less dry than the scientific norm. If want to wax lyrical
about your topic, here is the place to do it. Try to make the reader want to read the
kilogram of A4 that has arrived uninvited on his/her desk. Go to the library and read
several thesis introductions. Did any make you want to read on? Which ones were
boring?
This section might go through several drafts to make it read well and logically, while
keeping it short. For this section, I think that it is a good idea to ask someone who is not a
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How to Write a PhD Thesis
specialist to read it and to comment. Is it an adequate introduction? Is it easy to follow?
There is an argument for writing this section---or least making a major revision of it---
towards the end of the thesis writing. Your introduction should tell where the thesis is
going, and this may become clearer during the writing.
Literature review
Where did the problem come from? What is already known about this problem? What
other methods have been tried to solve it?
Ideally, you will already have much of the hard work done, if you have been keeping up
with the literature as you vowed to do three years ago, and if you have made notes about
important papers over the years. If you have summarised those papers, then you have
some good starting points for the review.
How many papers? How relevant do they have to be before you include them? Well, that
is a matter of judgement. On the order of a hundred is reasonable, but it will depend on
the field. You are the world expert on the (narrow) topic of your thesis: you must
demonstrate this.
A political point: make sure that you do not omit relevant papers by researchers who are
like to be your examiners, or by potential employers to whom you might be sending the
thesis in the next year or two.
Middle chapters
In some theses, the middle chapters are the journal articles of which the student was
major author. There are several disadvantages to this format.
One is that a thesis is both allowed and expected to have more detail than a journal
article. For journal articles, one usually has to reduce the number of figures. In many
cases, all of the interesting and relevant data can go in the thesis, and not just those which
appeared in the journal. The degree of experimental detail is usually greater in a thesis.
Relatively often a researcher requests a thesis in order to obtain more detail about how a
study was performed.
Another disadvantage is that your journal articles may have some common material in the
introduction and the "Materials and Methods" sections.
The exact structure in the middle chapters will vary among theses. In some theses, it is
necessary to establish some theory, to describe the experimental techniques, then to report
what was done on several different problems or different stages of the problem, and then
finally to present a model or a new theory based on the new work. For such a thesis, the
chapter headings might be: Theory, Materials and Methods, {first problem}, {second
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problem}, {third problem}, {proposed theory/model} and then the conclusion chapter.
For other theses, it might be appropriate to discuss different techniques in different
chapters, rather than to have a single Materials and Methods chapter.
Here follow some comments on the elements Materials and Methods, Theory, Results and
discussion which may or may not correspond to thesis chapters.
Materials and Methods
This varies enormously from thesis to thesis, and may be absent in theoretical theses. It
should be possible for a competent researcher to reproduce exactly what you have done
by following your de***ion. There is a good chance that this test will be applied:
sometime after you have left, another researcher will want to do a similar experiment
either with your gear, or on a new set-up in a foreign country. Please write for the benefit
of that researcher.
In some theses, particularly multi-disciplinary or developmental ones, there may be more
than one such chapter. In this case, the different disciplines should be indicated in the
chapter titles.
Theory
When you are reporting theoretical work that is not original, you will usually need to
include sufficient material to allow the reader to understand the arguments used and their
physical bases. Sometimes you will be able to present the theory ab initio, but you should
not reproduce two pages of algebra that the reader could find in a standard text. Do not
include theory that you are not going to relate to the work you have done.
When writing this section, concentrate at least as much on the physical arguments as on
the equations. What do the equations mean? What are the important cases?
When you are reporting your own theoretical work, you must include rather more detail,
but you should consider moving lengthy derivations to appendices. Think too about the
order and style of presentation: the order in which you did the work may not be the
clearest presentation.
Suspense is not necessary in reporting science: you should tell the reader where you are
going before you start.
Results and discussion
The results and discussion are very often combined in theses. This is sensible because of
the length of a thesis: you may have several chapters of results and, if you wait till they
are all presented before you begin discussion, the reader may have difficulty
remembering what you are talking about. The division of Results and Discussion material
into chapters is usually best done according to subject matter.
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Make sure that you have described the conditions which obtained for each set of results.
What was held constant? What were the other relevant parameters? Make sure too that
you have used appropriate statistical analyses. Where applicable, show measurement
errors and standard errors on the graphs. Use appropriate statistical tests.
Take care plotting graphs. The origin and intercepts are often important so, unless the
ranges of your data make it impractical, the zeros of one or both scales should usually
appear on the graph. You should show error bars on the data, unless the errors are very
small. For single measurements, the bars should be your best estimate of the experimental
errors in each coordinate. For multiple measurements these should include the standard
error in the data. The errors in different data are often different, so, where this is the case,
regressions and fits should be weighted (i.e. they should minimize the sum of squares of
the differences weighted inversely as the size of the errors.) (A common failing in many
simple software packages that draw graphs and do regressions is that they do not treat
errors adequately. UNSW student Mike Johnston has written a plotting routine that plots
data with error bars and performs weighted least square regressions. It is at
http://www.phys.unsw.edu.au/3rdyearlab/graphing/graph.html). You can just 'paste' your
data into the input and it generates a .ps file of the graph.
In most cases, your results need discussion. What do they mean? How do they fit into the
existing body of knowledge? Are they consistent with current theories? Do they give new
insights? Do they suggest new theories or mechanisms?
Try to distance yourself from your usual perspective and look at your work. Do not just
ask yourself what it means in terms of the orthodoxy of your own research group, but also
how other people in the field might see it. Does it have any implications that do not relate
to the questions that you set out to answer?
Final chapter, references and appendices
Conclusions and suggestions for further work
Your abstract should include your conclusions in very brief form, because it must also
include some other material. A summary of conclusions is usually longer than the final
section of the abstract, and you have the space to be more explicit and more careful with
qualifications. You might find it helpful to put your conclusions in point form.
It is often the case with scientific investigations that more questions than answers are
produced. Does your work suggest any interesting further avenues? Are there ways in
which your work could be improved by future workers? What are the practical
implications of your work?
This chapter should usually be reasonably short---a few pages perhaps. As with the
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