Longer monographs should have an odd number of chapters [the Internet,1700-xxxx].

Does this rule also apply for papers? I've got a paper with four chapters and I'm wondering if I should make it five. I could split up the outlook & conclusion part, but that would result in two really short sections.

What does the style police suggest?

  • 19
    Where did this rule come from? I've never heard of such a thing, and I can't think of any good reason why anyone would care about having an odd number of chapters. I found a few web pages that refer to this rule, and the ones I found all seem to lead back to www0.cs.ucl.ac.uk/staff/c.clack/phd.html. As best I can tell, that page is just one person's peculiar opinion. (The web page claims he "has a reference to back this up", which suggests the opinion is controversial, but it doesn't actually give the reference.) Dec 19, 2013 at 14:22
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    I agree: I've never heard of this rule, and it sounds utterly bizarre. Numerology?
    – Dnuorg Spu
    Dec 19, 2013 at 14:37

3 Answers 3


I don't think that any style guide or policy (besides maybe some journal about aesthetics in writing) will force you to an odd or even number of sections or chapters. A scientific text should get the number of chapters it needs and not a number that fits aesthetic principles–basically you write it to tell the scientific community about your findings and not to please them.

If you manage to write a scientific paper in Haiku form, this will be nice but it may also make some referee think you don't take your research serious enough. More or less the same holds for odd or even chapters. If you force the text to fit a certain number of chapters by dividing a chapter into two pieces, the reviewers might also consider that bad style.


There's something of a story that "having an odd number of chapters in your thesis" will make it more likely to get past the committee, or something like that. For example, in this personal website about theses, the author states that "Chapter headings - use 7 or 9! An odd number of (total) chapters gives a balanced appearance to the work (CC has a reference to back this up)."

I confess that I heard this as well when I was writing. I didn't end up structuring my thesis as a result of that advice but I heard it too. In the end, there's a 50% chance that your paper will have an odd number of chapters after you structure it. :)

Since I cannot find any other substantive evidence (other than the UCL link above) about the number of chapters in a thesis I must conclude that, at best, the effect of the number of chapters on the quality of a thesis is unknown; ostensibly, the odd or evenness of chapters having no effect would probably apply to scientific papers and scientific journal articles as well.


You write as many chapters as you need in order to get your message across. this applies to all types of writing, papers, reports or theses. I am sure some people might avoid 13 chapters or whatever number they feel unsettled about, but that will not have anything to do with scientific writing. Likewise there is nothing that says any form of scientific writing needs a certain number of chapters. That said, the Introduction-Methods-Results-and-Discussion (IMRaD) format, which forms the basis for most scientific papers, leads to four main chapters and in addition an abstract and a Conclusions chapter. Again, this is because it is a standard logical form not a "magic" number.

There are, however, many other typographical rules that influence the formatting of pages and chapters. For example, a chapter should start on an odd page number to follow traditional rules. There are thus many aspects of typesetting that influences the format of printed text but not the number of chapters.

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