If you were going to copy someone else's writing, would the Unabomber be your first choice of someone to copy from, someone who would react well if your plagiarism were discovered? No, right? Dănuţ Marcu thinks differently...

On the subject of plagiarism, I was also interested to see an article yesterday on plagiarism detection in the arXiv. With well-tagged author information and easy access to source code, the arXiv makes a good test set for plagiarism detection, and the authors of this article successfully detected some plagiarism, including plagiarists who copied from other plagiarists. The total is only about 0.5% of the content of the arXiv, but even that much is too much. I was a little concerned to see, though, that the authors view copying large chunks of text from ones own papers into a Ph.D. thesis as unethical, even when properly cited; they feel this sort of material should be blockquoted instead. Of course the thesis should clearly state that the work comes from certain papers, but I think I have seen more Ph.D. theses that did copy in this way than those that didn't.



What about if the papers copy large chunks of text from the thesis?

I'll note that the editors of Physics of Fluids, whom I asked about this because it will likely be of practical relevance to me, explicitly said that having material in one's dissertation did not count as "prior publication" under the "the paper must be new material, not previously published" clause of their requirements, and that they had no problem with the practice. (Going the other way, because of the copyright transfers on the papers, does require explicit permission, however.)

I've also copied large blocks of introductory material from one year's conference paper to the next. I see no problem at all with that; it's not masquerading as new results.


My feeling is that failing to make conference and/or journal papers from the results in your thesis is generally a mistake, because if you don't publish the results more widely the rest of the field will ignore them. Some journals do have a "30% new material" rule, which I've mostly heard of regarding conference and journal papers describing the same results, but which I imagine could also apply to theses, though.

None: Self-quoting

There was an ACM survey a couple of years back on the subject of plagiarims and the field was completely divided when it comes to self-quoting in theses as well as introductory parts. The opinions ranged from completely ok, to somewhat questionable to totally unacceptable. In contrast, all other scenarios posed in the survey had near unanimous responses as to their appropriateness.

11011110: Re: Self-quoting

Thanks. That doesn't sound very surprising, actually. I don't suppose you have a link? I know Kobourov had something in CACM recently on self-plagiarism, but what you describe a little different.

In case you don't have a subscription for the CACM link, there's a preliminary version on the web site for Stephen's self-plagiarism analysis software.

None: Re: Self-quoting

When you referee a paper, how come that you reject that paper and write a paper based on it?

11011110: Re: Self-quoting

My understanding of the ethics of that sort of situation is that anything one receives to referee is confidential, and must not be used as part of one's own research until such time as it appears publically in some other way. Do you know of a specific situation where these ethics were violated?

In any case I'm not sure what this has to do with self-quoting.