The 80:20 Principle and Thesis Content

The 80:20 Principle (Pareto’s Law)

They say that moving house is one of the most stressful things you can do (along with getting married or divorced). Generally speaking, you plan for the big stuff- moving the sofa or the washing machine- well in advance, but these usually aren’t the things which cause the most stress. The problem is that the small number of things which make up the most obvious bulk are only a fraction of what you actually own. The overwhelming majority of your possessions are tiny, but each requires roughly the same amount of thought.

Some of the smaller items are, of course, genuinely valuable and important, but what tends to happen is we spend most of the time fretting over meaningless crap. A bus ticket that reminds you of holiday 6 years ago. Old clothes that you never wear, but are still perfectly OK.  Notes from your undergraduate degree you’ll probably never look at again. Things which you put in a drawer because they might be useful someday. Every single one of these trivial items requires a decision, some mental input and physical action. It’s only when you’re exhausted, hungry, and completely stressed out that you finally throw everything in a bin bag and dispose of it forever.

Not all efforts have equal output. This is one of the core principles of modern economics, laid down by the controversial Italian economist, Vilfredo Pareto (1848-1923). Pareto noticed that in a vast range of circumstances, a small proportion of inputs accounted for the majority of results. He noted, for example, that 80% of the wealth was owned by 20% of the population, and that 20% of the pea pods in his garden produced 80% of the peas. Though the exact proportions vary, it’s generally applicable that small factors account for the majority of results, whether positive or negative.

As a PhD student, you’ll know that a tiny amount of your research time (probably much less than 20%) produces the majority of your results. That one day when everything just went perfectly, or you had that sudden insight that made up for months of getting nowhere. It doesn’t mean the rest has no value, it’s just that it’s unevenly distributed.

You should think carefully about what you put into your thesis, but approach it with the 80:20 principle firmly in mind. Not all potential thesis content is of equal value. Of everything you could write about, which aspects of your research are the most interesting, innovative or important? These should be the focus of your efforts, spending the majority of the time talking about the minority of things which add the highest value to your thesis.

Often, knowing what to leave out can be just as important as what you put in.

Write with the reader in mind

Every writer should write with their audience in mind. You have the advantage of knowing who your audience is;

·Your supevisor / advisor

·Future students following on from your work and, most importantly,

·The examiner

So what’s going to be interesting, useful or important to these people? It may sound obvious, but if something isn’t interesting, useful or important, why put it in? Remember that the examiner is an academic, and therefore busy. They do examinations as part of the system of mutual favours which underpin the academic system, and your thesis is an interruption of their time.

Imagine if someone comes to you during work and asks you to meticulously read through a 300 page document and interview the writer in a month’s time? No matter how much you have in your schedule, you feel duty-bound to comply. This is essentially what happens every time a thesis is up for examination.

So give them something worth their time, and don’t waste pages, time and effort trying to make the thesis longer just for the sake of bulk.

Keep it brief

Often, the best theses are short. John Forbes Nash, the American mathematician who laid the foundations of game theory, Nobel Prize winner for Economics in 1994, and subject of the biography,  A Beautiful Mind, wrote a total of 28 pages for his doctoral thesis, yet it was 28 pages of quality.

OK, so science and maths theses tend to be shorter, and to get away with a thesis that brief is unusual; Nash’s work is among the most important of the 20th Century. But if your work isn’t quite that exceptional, and you’ve written everything you think is interesting, useful or important, there’s absolutely no argument for bulking out a thesis with a bit more mediocrity.

It seems that perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

-Antoine de Saint Exupery, Terre des Hommes (1939)

If, at any point, the reader starts skipping through looking for the next interesting section, you’d have been better off cutting.

This is especially true of…

Literature Reviews

If you have a 3-foot high stack of research papers on your desk, the aim of a literature review is not to cite them all. Don’t, under any circumstances, take the telephone-directory approach! The aim is to highlight the few which have the highest value, applying the 80:20 principle.

Out of every hundred research papers you come across, there’ll be a relatively small proportion which have actually been useful to you. You should spend 80% of your time and energy on the 20% which are most important, rather than the other way round.

If the aim is to show your broad knowledge of the literature, then you also need to show the examiner that you can separate high-quality, relevant work from the background noise. Anyone can list a huge number of papers containing a certain keyword, but it takes some insight to be able to select only the most interesting, useful and relevant few.

Applying the 80:20 principle across the entire thesis,  it becomes far easier to create a coherent flow when you avoid digressions into trivial detail. The result is a thesis which is easier and faster to write, containing only the highest-quality, most interesting work, which an examiner will actually want to read.


I’m always interested in other people’s views, especially if you disagree with me! Leave your comments below and share your insights.

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  1. Emma The Viking says

    Thank you !
    I am about to embark on a literature review so I will try and adopt the 80:20 principle.

    I have made my research topic quite narrow so that I can hone in on a particular field without running out of time and to specialise.
    This may be a simple and quite obvious query..but for someone like me embarking on research for the first time..
    What if you start doing your literature review and you realise that perhaps you should widen your research field or take a slight turn , investigating some other type of technology for instance which may seem more appropriate for an application.?! Does this happen frequently ? Do you stick to your original idea , making side notes to your discoveries or do you make room for these realisations and change your research focus ? Is that what a PHD is all about ? Constantly evolving your ideas and knowledge ?

  2. Maria says

    I am thankful for your great tips…
    Have you come up with a template yet? I think it could be of a great help.

  3. jameshayton says

    Good suggestion Anita. I’m working out how to make a generic template that people can adapt to their own use.

    You don’t need to plan every day rigidly, in fact there need to be some flexibility within a fixed timetable. Dividing chapters into sections, and sections into sub-sections is enough, then as you write you’ll usually find that it takes on it’s own structure as ideas become clearer as you write about them.

  4. anita adnan says

    James, what you wrote here makes so much sense! and now i know how to choose the quality articles and highlight them, instead of reporting everything:)

    a suggestion – perhaps if you can create a template (3 months duration) and show us how to achieve the end – with some examples of your own work- that would be great. i am now looking at my 3 months schedule and trying to break down the subtopics so that i have a clear idea of what to write everyday. is that how you do it?

    keep up the great job, i will continue to spread this excellent resource to my friends who are in pain trying to put eveything together ;-)


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