I'm working on my individual dissertation in finance. This thesis tests the low-volatility factor on European markets. The core methodology is creating Fama and French portfolios, testing the new low-volatility factor with the Carhart model and a transaction costs analysis with R.

A friend of mine, who is also writing his thesis this semester, uses the same metrology to test the existence of a new momentum factor in the European markets. Therefore, we developed the core R code together. Although our dissertations are completely different, since we both test other factors, we do use the same code. Would you consider this plagiarism and how do I cope with this issue?

  • 8
    I would not think so, for instance no one would ever consider it plagiarism if you used the base lm(..) function for linear regression - or some other function. I see your concern, so I would advise that you run this by your advisor. Perhaps you should simply mention somewhere in the thesis that you co-wrote the code with student X.
    – Repmat
    Commented Oct 28, 2015 at 12:54
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    You might consider releasing the code on github as an open-source project. It could add to your citations if it is picked up and used by others.
    – Aaron Hall
    Commented Oct 28, 2015 at 19:17
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    Just clarifying that the code was a result of joint work with X should be enough to get (very) clear of plagiarism territory. Usually, huge fractions of thesis material were created with co-authors, so why should code be special?
    – Raphael
    Commented Oct 29, 2015 at 6:48
  • @AaronHall Thanks, we put some thought to this and we are willing to make this an open-source project. However, I'm wondering if there is an alternative to Github which is more focused on finance / factor investing and/or MATLAB?
    – Tim
    Commented Oct 29, 2015 at 12:23

1 Answer 1


Plagiarism is copying someone else's result and presenting it as an own result. It doesn't seem you're planning to do that.

In general, there shouldn't be a problem to use a jointly developed software core for research in your and your friend's dissertation. Research is a lot about collaboration, so I'd view that rather positively. But it will be important that you distinguish results that were obtained jointly from individual results, and that you agree on that beforehand to avoid potentially difficult discussions down the road. Things to clarify would include:

  • In how much detail do your dissertations need to describe the jointly developed core, and how much overlap is acceptable there? That is something you need to discuss with your advisor as well. It may be problematic to include a substantial amount of jointly written text in the individual dissertations.
  • Is there potential for a joint paper that you publish independently of your theses to describe the core software? In your dissertations, you can then simply refer to that paper and avoid overlapping text there.
  • Can you agree on specific contributions that everybody made to the software, have each of you focus on that for his dissertation, and refer to the friend's dissertation for the other part?
  • 9
    I think your answer pretty much covers it. There is one more point though - acknowledgement. Most dissertations have space for acknowledgements which can be used for thanks with regards to collaboration. Also, in the case of a PhD in the UK at least there would be paperwork where details of collaborative work are supposed to be entered.
    – DetlevCM
    Commented Oct 28, 2015 at 13:17

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