Notes on Essays and Dissertations
How to write an essay
An essay is not just a report, it's an argument. A good essay describes a
thesis, presents evidence for and against the thesis and analysis of that
evidence. Analysis of evidence should show how the evidence relates
to the thesis as well as pointing out any points that aren't fully supported.
Science is not meant to be propaganda --- a good scientific essay mentions
under what conditions the thesis may be wrong, how probable these conditions
are, and how they could be recognised. Most essays end with a conclusion
which is a reiteration of the thesis with a summary of the argument to support
Every paragraph of an essay is itself a smaller essay --- each one should
have its own point. Each sentence should contribute to the paragraph, and
each paragraph should contribute to the essay.
Many students develop a bad model of essay writing in school: "First
I will learn, then I will tell you what I learned. I will read something,
then summarise or report on what I read." Good writing is much more
than this. The process of writing requires organising and communicating
your thoughts --- you are your own first reader, and first critic.
Writing, like any kind of teaching or argument, helps you understand the
material you are presenting better. Often the process of writing will show
you holes in your reasoning, beliefs that haven't been fully supported.
These holes lead you to further thought and further research.
How to write a dissertation
A dissertation is more of an essay than a report. Dissertations contain
reports, but their fundamental structure is that of an essay. They
should have a thesis which is being demonstrated. The reports come
in describing extensive evidence and the means by which it was gathered.
Dissertations which describe software development projects are still essays.
Their theses might take the form "An XXX needed to be built, and I have
succeeded (or partially succeeded) in building it." Both halves of
this thesis need to be supported: the motivation for the project must be
described, and evidence must be presented that you have met the criteria
of your project.
The target audience for a dissertation is not just your supervisor --- it is
your peers. Most readers of a dissertation will be other students,
other developers or other scientists who are interested in at least some
of the areas covered in your dissertation. Some of these readers will
only be interested in one or two paragraphs you wrote about another paper
or project. Some of them will be doing a similar project and will
want to understand the decision process that lead to the path your project
took. Some may be trying to replicate, test, extend or build from your
work. These readers will need a full report of your methods, assumptions
How to write a research article
Research articles are a little like dissertations, but they have to be direct,
to one point (if you have more points, write more papers) and
formulaic. The reason research articles should be formulaic is because
scientists need to read many of them, so it should be easy to find exactly what
you need to read. The one point of a research article is like the thesis of an
As with a dissertation, it is critical in an article that you provide
information so someone else can replicate your work and compare your
results to their own. This belongs in a section called Methods.
and the statistics used to analyse them
should be in a Results section, which comes after
Methods. Either the Methods section or the introduction to the results
section should also explain exactly what
experiments you have run and why. The bulk of the Results section describes the
procedures and outcomes of usually several experiments precisely. After the
Results section is a
Discussion section, which describes the implications of your research,
including what your results imply about other people's work. This is the
one place in the paper where you are permitted to speculate a little,
but any speculation should be well supported. The Conclusion is only a
summary of the main points of the paper, possibly including a summary
of your intended future work. No novel ideas should be introduced in
I have started at the heart of the article, but it is worth mentioning that
articles must start with very specific titles that make their contents clear,
good concise abstracts, an Introduction that motivates the research by
explaining the problem thoroughly and how your research addresses it. There
is often next a Background section which goes into more detail on the existing
state of the art (see further below the Literature Review), though this
information may be just included in the Introduction.
Components of a dissertation
A dissertation needs all of the following components.
Notice that component
does not mean chapter. These things may not deserve entire chapters to
themselves. Further, the argument, not the components, should dictate how you
structure your dissertation. But every dissertation should have all the above
- Introduction: should explain the thesis
and how the dissertation is laid out. Some people will only read this
and the conclusion.
- Conclusion: explains the thesis
again, and summarises how and to what extent it was defended. Most
people read the conclusion of a dissertation first (or immediately after
the title and abstract) and decide whether to read the rest of it from there.
- Motivation: why is the thesis interesting?
Why was this work done?
- Background: what work has been done
in this area before? What of it proved useful to this dissertation?
Why was it used if it was used, or ignored if it was ignored?
- Methods: how was the novel research
(the programs or experiments) in this dissertation done? Another student
who has gone through your course but not necessarily taken the same classes
as you should be given enough information or pointers to other sources of
information to be able to replicate your work. For a software project,
this will include a high-level description of the architecture of the system
as well as more technical details.
- Results: outcomes of all experiments.
For software, descriptions of the final system as well as initial systems.
Significant changes in direction should be documented and explained
--- they are probably the result of something interesting you learned. Description
of a system includes an analysis of its performance (e.g. speed, domain of
- Implications: a summary of what you have
learned and what you think it implies. What would you do differently,
given what you have learned. What does the outcome of your dissertation
imply about the existing literature and/or systems described in your Background
- Future Work: what would you have
done if you had more time? What should other people do with similar
or slightly different interests?
The Review of Literature is a very important
part of a dissertation. Again, many people who read your dissertation
may be most interested in your literature review. Once you have spent
months (or years) on a topic, you become an expert. This makes your
perspective on the rest of the field around your own work particularly
The Literature Review is not listed as a component because
it is an integral part of your evidence, and it may potentially be in many
different locations. For example, you would
expect some literature review in the Background and in the Implications.
Normally there will be a phase of heavy reading toward the beginning of your
research project, then a period of heavy coding, and finally another burst
of reading during the final write up.
When and why to reference
Science works much the same way as evolution. Each piece of work
inherits most of its bulk from the good, proven ideas in the existing
literature, but each experiment adds some novel variation, some new
ideas, and then tests those new ideas against the old. A scientific
journal article needs to show that you know and understand the
existing literature, and that you understand and can prove your
contribution to it. The way you show that you know the existing
literature is not only by listing it in the back, but by referencing
appropriate citations in the text after any claim that relate to
previous knowledge. This allows you both to validate your claims
(evidence from other people's experiments can be just as central to
your arguments as evidence from your own), and also lets the reviewer
(and later, the reader) know that you are up-to-date.
Often when you read someone's paper, you might think (for example)
"Ah, if they believe that, they haven't seen A's newest work." So, if
you are contradicting A, you have to say "This is in contrast to A
(2005), who is wrong because..." Another common thing a reader might
think is that "B has already done this." If it is true B did (and
published) something exactly like you did before you did it,
then you work won't be worthy of publication. So if you know B's work is like
your own, you need to say something like
"This is similar to B (1993), but we have made an improvement in this
One exception to this rule is replication, that is, when you deliberately set
out to test a published result that is not yet widely accepted.
In this case it is perfectly allowable to say, "This provides further evidence
that B is
correct, and our study provides important corroboration for B's
theory." This is especially useful if someone else has
published saying B is wrong and you can cite them as well. Or if in attempting
your replication you discover that B didn't really make it very clear how to
achieve their result, then you can report the extra information. There is
always a chance you will find out that B made a mistake, and this can be very
publishable, but you also have to be very, very careful that you are right
before you say that someone else is wrong.
Structure of a project and its dissertation
Best practise for completing a dissertation often will have reading, writing
and coding occurring
your project. Simple prototypes or pilot studies should be done very
early in the project, because they will help you understand the material
you are reading. This will also help you get a grasp on the difficulty
of the problem you are addressing, which allows you to adjust your schedule
and expectations accordingly. Similarly, when during coding or
you encounter difficulties or make discoveries, then you should take time
to search the literature for more information on your new problem or
During the final writing phase, nearly all students discover that they
cannot support all of their assumptions or claims, and therefore need to
do more reading, run more experiments, or run further
some of this should simply be documented in the Future Work section, it is
best to leave some time for doing this research.
As I said earlier, the components above do not necessarily correspond directly to chapters. Often
Motivations are included in the Introductory chapter, or Implications are
included with either after Results, or with Future Work in a chapter called Discussion. On the other hand, there
might be several chapters covering different phases of the project (e.g.
3 different versions of a program) each of which contain Methods, Results
and Implications. Background might be split between a chapter explaining
Motivations and one explaining Implications. Many examples of dissertations
are available from the front office, from your supervisor, or on the Internet.
More general writing advice:
Good writing is part of what makes science and engineering work. Everyone has
different information acquired over their lifetimes, so anyone can make
a critical discovery of a hole in a literature, or a relation between two
previously unconnected ideas or areas of work.
page author: Joanna Bryson
last updated: 29 December 2005