The federal definition of plagiarism does not include self plagiarism–and that is a good thing. For example, in one of my manuscripts I wrote these words:
“Male Sprague Dawley rats (250-350 g, Hilltop Lab Animals, Scottdale, PA) were housed on a 12-hour light cycle in polypropylene cages with cedar bedding and maintained on 5001 Laboratory Rodent Diet (Purina Mills, St. Louis, MO).”
The next manuscript, which is part of the same project, will contain the same sentence. I see no reason to modify it. It contains the information it needs to, it is clear and concise. (You might object to the passive tense, but to put it in active tense I would have to say “I housed the rats” and the subject of the sentence is the rats, not me. While the ubiquitous passive tense of science writing annoys me– I almost said “is annoying”– there is a time and place for it and good reason that it’s so prevalent.)
In fact, I would be pleased if many other people used essentially that same sentence, changing only the details. It is frustrating to read a paper that does not specify what type of plastic the cages were or what kind of food the rats received or worst of all, the gender of the rats! (The assumption is male. I have a problem with that. I also have a problem with the default use of male rats, but I didn’t have control over that in this particular study.)
This manuscript has 8 authors. Presumably each of them could use any part of this manuscript in another manuscript and it would be self plagiarism and therefore not plagiarism. Suppose one of them writes another manuscript that has other authors on it and one of the others authors wrote a 3rd manuscript that has that sentence but does not contain any of the authors on the 1st manuscript. Would that be plagiarism? Do you get to inherit words in that way?
With the example sentence I gave, no one would care. But you can easily imagine the 6 degrees of separation causing a self plagiarism problem at some point.
Here is another example: “All experiments were approved by the local Animal Care and Use Committee and were carried out in accordance with guidelines from the National Institutes of Health and from the International Association for the Study of Pain for pain research in animals.”
This is standard language and this sentence or something very similar to it should be included in any publication of animal experiments. Most journals require it. There’s only so many ways to say it. I doubt that I created that sentence. I don’t know where I got it from, but probably something along the lines of the 6 degrees process I described above. There’s only so many ways to say it, and if you get too creative, someone looking for that particular sentence will have problems finding it, which could have regulatory implications.
Well, I’ve enjoyed this little interlude in writing my manuscript. I have not resolved anything, but I have succeeded in a spot of procrastination.