Thesis-Writers Anonymous

Dr. Andrew Broad
Computer Science
Thesis-Writers Anonymous

I'm writing this to share my experience of thesis-writing (and other aspects of PhD research) with CS710, and to help myself by trying to write it up in one place (it is in no way intended to be a substitute for reading through my CS710 course summaries, however). I may well revise this page in the future.

Much of the advice on this page comes from my supervisor, Nick Filer.

I do not intend this page to be taken as gospel. Feel free to make suggestions or alternative points of view.

Aaron Sloman's Notes on Presenting Theses is quite possibly the most useful thing I've ever read when it comes to advice on thesis-writing! It focuses on the strategic level, and covers everything that should be included in a thesis right down to the nitty-gritty details. It seems to talk to you as directly as anything could that doesn't know what your particular thesis is about. All thesis-writers must read it! Aaron Sloman is also willing to receive criticisms, comments and suggestions for improvements.

I am a PhD student in my fourth and final year. I started as a research student here in September 1997, and submitted my MPhil thesis in December 1998 - over two months late. The biggest reasons for the delay were that it was a brain-dump (I tried to write down everything I knew about my topic - I didn't know how to leave things out) and that I am a perfectionist (I won't submit anything until I'm sure I've done my utmost - most of the two months of overrun were proof-reading and editing, including moving large chunks to appendices to keep the length of the main text down). In the end, my MPhil thesis was 339 pages long - larger than most PhDs! - with about 150 pages of main text.

The lesson here is that a thesis should be focused, not an attempt to capture everything you know about your field. You have to focus on the specific problem you're trying to solve, while at the same time showing a sufficient awareness of the field in general (i.e. the literature).

I was highly successful as an undergraduate here, gaining a first-class BSc, and winning the Williams/Kilburn medal for being the outstanding final-year student. However, research is a huge struggle for me, because it's so vague - it's not like a taught course where you have concrete targets to fire your arrow at. I am so far behind now that I'm having to register full-time for a fourth year, and have strictly until 30th September 2001 to submit my PhD thesis. I started writing my PhD thesis in the December 2000 vacation, but put it on hold until April 2001 as I haven't finished my practical work.

How to structure the thesis

There are two extreme ways to structure a thesis:

An implementation-oriented structure is appropriate for an undergraduate project report, and will even pass for an MPhil, but for a PhD you really need to adopt a contribution-oriented structure. PhD examiners do not care about the implemented system - what they really care about is the contribution to knowledge, so it's very important to identify the contributions of your work, state them clearly in the thesis, and organise your thesis around them. Everything in the thesis should relate to one of your contributions.

A contribution-oriented thesis can be visualised as a diamond structure, with lines going out from the introduction chapter to the contribution chapters, and from the contribution chapters to the conclusion chapter.

I thought I couldn't do a contribution-oriented structure at first, because my contributions are so intertwined (I have one overarching contribution and four subcontributions). You may have to question what your contributions are, and how they should be organised. Get the structure of your contributions clear before you derive the structure of your thesis.

It is instructive to take a few PhD theses, read their first and last chapters to identify the contributions, and to see how their contributions fit into their thesis structure.

Planning the thesis at the strategic level

I plan my thesis in detail before I write the actual text. I take a top-down approach: identify the chapters, identify the sections and subsections, and identify the major points to be made. Identify the preconditions and postconditions of each part, so that you know what the dependencies between the various parts are, especially if you're going to write them out of turn. Expect to have dilemmas about where things belong, and circular dependencies. You might have to move things around, and this is obviously easier to do to the plan before you write the full text.

Start by planning the conclusion chapter. Knowing what your conclusions are will help to focus the rest of the thesis and keep it coherent.

Consider writing the introduction and especially the conclusion chapter last. My supervisor insists that the introduction chapter is a very bad place to start! This is because it needs care to avoid a lot of irrelevant detail. It's particularly important that the introduction (especially the aims and objectives section) and the conclusion are coherent with each other.

Here are some hints about how to write a thesis plan:

  1. What points are you actually going to make? For example, in a literature review, for each reference:

  2. Write down the preconditions explicitly. What do you have to know before you can write the answers to 1? What does the reader have to know before they can understand this? What assumptions are you making about the reader? What do you regard as absolutely obvious that other people might not? (This applies both at the tactical level and at the strategic level.)

  3. When thinking about the literature/your work, think about how it relates to your work/the literature.

  4. You may find that your plan contains circular dependencies, and that you have dilemmata about where to put things. To break a circular dependency, introduce the thing early on, leave the detail until later, and insert cross-references.


Evaluation is a crucial part of passing the PhD examination - how do you show that you have succeeded, and measure your success? This is a very difficult problem for me, and I wish CS710 would devote a week to evaluation. It's important to work out your evaluation criteria, and to make these criteria clear in the thesis - otherwise the examiners will judge you by their own, probably inappropriate criteria.

An important piece of advice I was given at my last end-of-year interview is to evaluate with respect to a specific application rather than thinking you can do some sort of generic evaluation. Who might your end-users be? Why would they be interested? What use would your work be to them?

There is thus a distinction between intrinsic evaluation (does it work?/performance measurements) and extrinsic evaluation (a demonstration that it is - or would be - useful in a specific application context). A PhD must have adequate intrinsic and extrinsic evaluation.

Know the weaknesses of your PhD. Write down a list of all the reasons you think your PhD could fail, and discuss it with your supervisor. This is a very valuable exercise because (a) if you know what the weaknesses are, you can work on them, and (b) you might find it's not as bad as you think! :-) Some things to consider for the list:

My tactical-level advice for technical writing

Miscellaneous hints:

The day-to-day process of thesis-writing

It's important to organise your time well, and try to get into a routine for thesis-writing. It's not easy because your situation will keep changing. It's a very individual activity, but I want to talk about how I do it.

I do not live at university - my house is an 80-minute journey away (walking, train, waiting, bus). That's when I do most of my reading - papers, and proof-reading my thesis (usually the bit I've just written). I generally do no work once I get home, which is usually between 21:30 and 22:00. I usually go to bed just after midnight, and I require 6h30m to 7h sleep to operate effectively.

On a good thesis-writing day (expect plenty of bad ones, though, when you just don't feel like it! ;-)), I arrive at university at 9:20 or 9:50 (depending what train I catch). It's good to start with editing the thesis according to the comments you've written on yesterday's draft (mainly tactical-level), because it's a gentle introduction to a day of thesis writing. If you don't take a comment on board immediately, insert it into the text of the thesis using special characters to delimit it, and don't forget to grep for such comments before you submit!

It's important to block out distractions, because it's easy to make excuses to put off starting work for the day, especially something as vague and difficult as research (concrete tasks are easier to get down to). My particular vice is emailing and surfing the Internet, so I have actually written a Perl script to keep me off until 17:00!

chmod +r
chmod -r
use Time::Local;

$day= (localtime)[6];
$hour= (localtime)[2];

if ((($day < 5) && ($hour < 17)) || (($day == 5) && ($hour < 15))) {
        print ("GET TO WORK!!!\n");
} else {

I usually do my main block of thesis-writing after lunch. Getting down to it is the hardest part, but it's possible to get on quite a roll if you're motivated, if you block out distractions, and if you're feeling alert. Unfortunately I am prone to mid-afternoon slumps, where my brain just packs in and I can't do any work. Such slumps can be combatted using coffee or stimulant drinks - I find the `V' stimulant (green can) to be most effective, and I have one every day with my lunch now. I also tend to be more alert in late afternoon/early evening, so I will often continue then (even if I have to sacrifice my Internet time! ;-)). You need to find out what works for you - what time of day you work most effectively, and how long you can work for in one sitting. If that would be working at night and sleeping from 8am to 4pm, then do it! ;-)

I record the time I spend working each day - thesis-writing, reading, programming, meetings with my supervisor, CS710-related activities, etc. I write it in my diary so that at the end of each day (and week), I can feel good if I've had a productive day, and guilty if I haven't put the effort in, so I know I have to buck up my ideas. It is good to have hobbies, and to devote a few hours a day to them, because it keeps you sane and enjoying life. It's best to leave hobbies until the end of each day, to avoid distractions, and to enjoy your hobbies without feeling "I should be working now". Interleaving hobbies with bouts of work throughout the day has the pitfall that it's easy to get sidetracked or absorbed in your hobby, so it's better to take a coffee break, have a 20-minute walk, or do something that's definitely going to be time-limited.

I go in to university on Mondays to Saturdays, and work at home on Sundays, taking copies of thesis files to work on the Mac at home (that's the joy of LaTeX, which compiles text files with embedded formatting commands rather than you have to use a special program to edit the files). If you have spreading versions of files like this, it's a good idea to put the time and date on the first line of each file every time you save it, which resolves any confusion over which version of the file is newer (it's also vital that you keep at least one regularly-updated backup of your thesis files on another file system). I also write the date on each printout (by hand).

The week-to-week process of thesis-writing

It's important to plan what you intend to achieve each week, and at the end of each week, to take stock of what you've done that week, and plan for the week(s) ahead. For this purpose, I write a weekly summary of up to one side of A4.

I'm within six months of my thesis deadline, and I have six chapters to write in that time, so I've planned to spend three weeks writing up each chapter and working on the plan for the next chapter, leaving a month before the deadline for proof-reading and editing (do not underestimate the time needed for this - that was one reason why I was two months late submitting my MPhil thesis).

When you start writing up a chapter, annotate your plan of that chapter with the date when you plan to write each section, and try to stick to your time-plan. I tend to allocate a day to each subsection. Leave some slack in the plan in case you fall behind. If time is tight and you fall behind on a day's target, it may be better to start tomorrow on the next section anyway, and go back and finish the unfinished section later - otherwise, you tend to dwell on a section or chapter too long, and end up falling behind significantly. Expect to leave some gaps as you go along anyway, because there are likely to be bits you're not ready to write right now, or that you're psyched out by.

It's important to get regular feedback from your supervisor. I generally show each chapter to my supervisor just after I've written the first draft, and the plan for the next chapter I want to write up. I'm currently writing Chapter 5 (my second full chapter to write up), and the plan for that went through several iterations over a period of two months before my supervisor said it was ready to write up. This was an incredibly frustrating and depressing period for me, but a thesis is likely to fail if it isn't written up with the right plan.

A good supervisor will discuss your thesis plan with you, asking you questions to which you may know the answers but haven't thought to include those points in the thesis, and identifying gaps that need further research before you can write them up properly.

A big dilemma for me is that students are encouraged to follow a `waterfall model' of research - finish the practical work before starting to write the thesis. I feel most uncomfortable with this, especially as I am anxious not to keep putting thesis-writing off when my back's to the wall time-wise. It's natural for someone like me to want to continue with practical work in parallel with thesis writing. The pitfall with this is that it's harder to keep the story coherent if practical work is still ongoing. Another pitfall is that you'll tend to concentrate on one for weeks at a time, while the other stagnates. If you do have to interleave thesis-writing with practical work, I think it's best to set aside specific days of the week for each activity - e.g. Mondays and Tuesdays for practical work, and the other days for thesis-writing (not forgetting CS710 on Wednesdays! ;-)). This is better than trying to do some of both each day, because you tend to spend the whole day doing one or the other.

Do not expect progress to be constant! Sometimes you might go weeks without writing anything, even if you've already written a chapter. There may also be certain times of year, such as Christmas, when you won't be doing much work. I have promised myself to take the Wimbledon fortnight off (I am an avid tennis fan). I think it helps if you identify such breaks in advance and treat them as milestones - planning to have written up Chapters X, Y and Z by then gives you something to aim for.

The final year of your PhD can be a very difficult period emotionally, when you're writing up the most important large document of your life, and you're pessimistic about the chances of passing (which could be a self-fulfilling prophecy if you allow it to affect your motivation). You might also be worried about what you'll be doing next year - pass or fail. I try to take it philosophically, and live for the moment. I've no idea what I'll be doing next year, and I'm not even going to think about getting a job until my PhD is all over. I've promised myself an indefinite break after my PhD, and looking at that time not as unemployment but as a time to indulge my hobbies gives me something to look forward to, and makes me want to make that final push for a PhD, knowing that the burden will soon be off my shoulders whether I pass or fail.

Miscellaneous advice from students' thesis presentations

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