This question was raised by Dave Clarke here.

When a textbook author approaches a topic in a novel way or presents a particularly interesting example, I believe that a teacher who creates lecture notes using this novel approach or interesting example would be doing the right thing to cite the originator of the approach or the example. Similarly, whenever I copy a clever (and clearly unique) problem from a textbook and give it as a question in an exam or an assignment, I try my best to indicate (in the exam or assignment paper itself) the source of the original problem.

Does anyone know of any written document indicating whether or not it is considered unethical to copy a published problem and put it in an exam or an assignment without citing it?

  • 3
    I don't know about ethics, but what you try to do can be impractical if the original author includes solutions. I guess offering the credits after students have to hand in exercises would work, then.
    – Raphael
    Commented Sep 13, 2012 at 7:55
  • 6
    Problems are much the same as jokes. And similarly, sometimes it's difficult to track the origin. Commented Sep 13, 2012 at 14:15
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    I'd like to thank all those who submitted answers. I have found them useful and have upvoted them all.
    – JRN
    Commented Sep 18, 2012 at 0:16

5 Answers 5


I'm a textbook author. I agree that it's hard to formulate a cut-and-dried answer to your question. One criterion to consider: If a colleague would compliment you on a copied problem or question because it was particularly clever or insightful, you should probably consider a citation. Stated differently, if you're getting academic credit (even if informal) for the contribution, cite the source.

  • 2
    Too subjective, just cite source to all problems in your notes/book. Better safe than sorry.
    – vonbrand
    Commented Sep 18, 2015 at 18:42

I think it's considered more of a courtesy rather than a requirement to credit someone who has developed a problem, provided that there is no new technical content introduced in the problem. On the other hand, however, if one is to use a problem in a problem set or examination completely unchanged, then some citation of the original source is certainly recommendable, as otherwise one is guilty of a copyright violation.

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    I'd think the question of citation and copyright violation are somewhat orthogonal to each other. Unless dictated by licensing terms (e.g. Creative Commons), copyright violations are still copyright violations even if you cite your source.
    – Daniel L
    Commented Sep 15, 2012 at 3:08
  • I agree with the other comment, and would also point out that copyright often allows you to use small portions (e.g., one chapter, or a handful of exercises) for teaching purposes. Commented Mar 19 at 11:20

Does anyone know of any written document indicating whether or not it is considered unethical to copy a published problem and put it in an exam or an assignment without citing it?

I know of no document that addresses examinations and assignments directly but reusing someone else's words or ideas is plagiarism. It doesn't matter the source, purpose, or intent. For teaching materials I think there is a little leeway in that plagiarism may be unintentional. I am sure that some the examples I use in my teaching ,that I think are my ideas, are in fact someone else's.


I am trying to give a point of view different from what some of the answers.

Citation is generally associated with new, clever or original creations. But sometimes it is very hard to know the origin. What if the author him/herself does not cite some examples or questions taken from someone else. How do you know they had the original idea? Often questions are borrowed modified and then presented. Should we take the credit for them or not? We learn some techniques of setting good and relevant problems from someone else and then we create new ones. Should we cite them?

What I mean to say is that it may not be practical and possible and even clear if we need to cite and I agree this may not always be the case. I guess that is why none of us has come across any such documents and guidelines.


This is a thorny issue. It comes down to copyright and license, and, particularly, what is and isn't copyrightable. If the problem is not copyrightable, then you can do whatever you wish. If the problem is copyrightable, you should assume it is copyrighted, which means you can't use it unless you have a licence to do so. The only way you are guarantee that you have a licence is to use that book in your course. If you require your students to purchase the book, then they are purchasing the license to use all of that content. You can then use the same content with them. Even providing a reference is not good enough if the material is copyrighted, and you don't have the licence.

If the problem is fundamental or factual, then it's probably not copyrightable unless there is something peculiar about the wording. Thrse questions can be complex. For example, the following would not be copyrightable:

What is the derivative of x3 + 4x?

What is the major product of the reaction between calcium carbonate and sulfuric acid?

Write the time-independent wavefunction for the electron in a ground state hydrogen atom. Then, provide the eigenvalues for this wavefunction with the kinetic energy operator.

Draw a simple set of supply and demand curves for a generic free market for a manufactured product. Describe or draw the effects of each of the following changes on the market: 1) discovery of a cheaper method of production, 2) closing of a plant, 3) government enforcement of a maximum price.

I'm having trouble coming up with a question that is copyrightable. Feel free to add one to my answer.

  • 6
    A complex problem that involves an extended set-up would probably be copyrighted. On the other hand, the underlying idea is not copyrighted, and could be used without any concerns about violations. It's the specific expression that's copyrighted.
    – aeismail
    Commented May 27, 2012 at 20:03

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