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In a follow up to his post on ‘When is enough reading enough for a doctoral thesis’, Ian Brailsford provides some fascinating metrics on the size of doctoral theses. Ian is Postgraduate Learning Adviser in the Libraries and Learning Services at the University of Auckland in New Zealand. 

By Ian Brailsford

The digitisation of doctoral theses is a great boon to current doctoral candidates: reviewing recent examples of doctoral work in their institution is only a few clicks away. New candidates can appraise doctoral work done by former scholars in their department to get a feel for aspects such as chapter structure, page length, academic writing style, and referencing conventions: reading a thesis to write a thesis as Cally Guerin recently advised. Moreover, they can readily access doctoral work globally and, with a bit of research savvy, probably locate a PDF copy of their supervisor’s doctoral thesis!

As a postgraduate learning adviser one of my regular weekly routines has been to check our digital repository to see which new doctoral theses have been uploaded. This reconnaissance is a nice way to see who has finished, who has been thanked in the acknowledgements, whether or not the thesis includes publications, and if I’m able to understand the abstract. Although a few new doctoral theses are embargoed, there are usually six or seven new ones to scan through each week.

Just over three years ago I started keeping an Excel spreadsheet to keep track of how many pages there were in each thesis and the number of chapters. Once I got a sample of 100 theses from 2015 I began looking for patterns in the data. This simple desk-top survey revealed that the average number of chapters was 7.17 with 189.6 pages. Since outliers, the short thesis (67 pages in maths) or long (460 in architecture), could potentially skew the average, I checked for the median length which turned out to be 178 pages. With help from two colleagues at the University of Auckland, Drs Liz Sowden and Brígida Figueira, we classified the 100 theses into STEM disciplines (n=76) and non-STEM (n=24).

We agreed to carry on with the audit and decided that 1,000 doctoral theses, 100 from each calendar year from 2008 to 2017, would form a robust sample size and allow for any changes in length and composition over time to be detected. Our repository sorts theses by year as one search option, so we typed the year into the search box to generate our sample of 100 theses for that year; since the number of doctoral completions has risen from about 250 per year in 2008 to over 400 last year, our survey is approximately 25-40% of the entire body of theses in our collection. We created our own protocol to ensure consistency of coding. Pages were counted from the first Arabic numeral to the final substantive chapter page and before the bibliography/reference list and any appendices. So our page count did not include the front sections (using Roman numerals) such as mandatory title page, abstract, table of contents, acknowledgements, preface, glossary etc. And we agreed that a page was a page was a page irrespective of font size, line spacing, and inclusion of tables, figures and illustrations. If it had a page number it was a page.

Most thesis tables of contents made it easy to discern the number of chapters: they were numbered in a conventional sequential format. Where numbering of chapters wasn’t used (usually in arts and humanities doctorates) we counted the larger-font headings that clearly signalled a separate section of the thesis. Finally, we took the practical decision that doctorates from our Faculties of Science, Engineering, and Medical and Health Sciences were labelled STEM and from the Faculties of Arts, Law, Creative Arts and Industries, Education and Social Work, and Business non-STEM, while acknowledging that the boundary between the ‘two worlds’ was porous.

After three years’ work, here’s the headline ten-year data from the 1,000 University of Auckland doctoral theses:

Average number of pages = 204

Median number of pages = 198

Average number of chapters = 7.55

In the sample of 1,000 theses only 23 had fewer than 100 pages and a further 65 theses were more than 300 pages in length. Just under half (n=486) were between 100 and 199 pages and the remaining 426 between 200 and 299. When it came to number of chapters, 604 theses had six, seven, or eight chapters; the seven-chapter thesis was the most common (n=229). There were 131 theses with five or fewer chapters (two chapters was the simplest thesis structure found) and 138 with ten or more chapters (20 chapters was the most complex).

For the period 2008 to 2015 we also explored differences between STEM and non-STEM theses (n=800). Generally, STEM and non-STEM theses had similar numbers of chapters as described above. However, STEM doctoral theses tended to be shorter than non-STEM theses. In our first year of data, 2008, the median length of a STEM thesis was 210 pages and 241 pages for non-STEM. However, since 2009, the median number of pages for a STEM thesis is below 200 pages and trending downwards towards 150 pages (in 2015 it was 159). Non-STEM theses hovered between 225 and 250 pages from 2008 to 2015, but over the last few years also appear to be trending slightly downwards (median of 223 pages in 2015).

Over our 10-year period the basic requirements for a PhD or named doctorate have remained the same. For PhDs, the maximum word length (including the front matter, bibliography/references and any appendices) is 100,000 words (60,000 words if it includes creative practice). The only changes have been (since 2011) the potential to submit a PhD with a creative component and clarification of the use of publications in the thesis. In addition, the average time to completion has dropped from over four years to 3.8 years.

When I looked at the 100 theses from 2008 and compared them to the 100 theses from last year, there were slight differences. The average length in 2008 was 227 pages with the median 217; last year the average length was 193 pages and the median 201. In 2008 there were an average of 7.93 chapters and last year 7.15. The ratio of STEM to non-STEM theses was similar, 69 STEM in 2008 and 64 STEM last year. It’s possible that the increasing number of our candidates taking the thesis including publications option and/or more timely completion might be correlating with the slight reduction in thesis length.

I’ve started using these ‘headline’ data in my doctoral writing workshops, especially the ‘Thesis structure’ and ‘Getting started with writing’ classes, to help new candidates gauge the likely length and composition of their doctoral thesis. We’re back into the ‘when is it enough?’ territory. Our Dean of Graduate Studies, at Induction sessions, tells new candidates that the maximum word length is a limit not a target! If they have to exceed 100,000 words, they need her permission to do so and a good reason as to why their doctoral work can’t be written up in fewer than 100,000 words. And she reminds them that there is no minimum word limit. So the general advice from the ‘get go’ is that the doctoral thesis that goes in for examination is a long as it needs to be, and preferably no longer than it needs to be so as to not try the patience of thesis examiners.

These ‘words to the wise’ are complemented with our data. I tell candidates that, irrespective of their thesis subject, if they work towards a thesis of six, seven, or eight chapters they are in good company. But if two chapters is enough that’s fine; likewise, if they require twenty there’s precedent in the repository. In either case, however, they will be an outlier. Candidates in STEM disciplines can think of their thesis as approximately 150 pages, whereas people in social sciences, arts and humanities are more likely than not to be writing a thesis over 220 pages. And the evidence in our repository indicates that you can write a thesis with fewer than 100 pages or more than 300 but these are not common. However, they might be the exception that disproves the rule of thumb.

I appreciate that counting chapters and pages is a crude mechanism to judge a doctoral thesis. If we went down to the number of words, we could have debates about what exactly counts as a word, especially for theses with equations, formulae, chemical symbols and the like. However, I stand by my position that as an adviser I have to give advice. Using the average thesis of seven chapters over 200 pages, thesis writers can be reassured that if ‘push comes to shove’ they could write just two pages per day over 100 days or a plan to write one chapter every two weeks and complete a thesis in about three months. Obviously writing a thesis is neither as simple nor as mechanical, but understanding that it’s not an insurmountable writing task is the point. My workshop participants are smart enough to know that when I talk about the probable number of thesis chapters and pages, these are approximations; the advice is given to help demystify the process of completing a doctorate. The truth is out there, researchable in the ever-expanding digital repositories of doctoral theses.

This is another crowd-sourcing post. My colleague across the road at Auckland University of Technology, Dr Anaise Irvine, has quantified the chapter and page length of doctoral theses in AUT’s repository with her results, albeit with a smaller sample, mirroring ours. Are there any other audits of thesis chapters and page length spreadsheets sitting on people’s desk-tops?


I would like to thank Liz and Brígida for the hours they put into counting chapters and pages!