I suppose that in some ways, self-plagiarism is similar to regular plagiarism. You are failing to acknowledge that some of what you're publishing now already exists in a published form. You are not properly identifying your sources.
It differs because you are not misappropriating the work of others. But, if you regard your previous published work as the work of another person (which in existential terms it is!) then you will treat it correctly in the now. Refer to it and reference it as you would anyone else's work. Do that, and you won't go far wrong!!
I suppose that in some ways, self-plagiarism is similar to regular plagiarism. You are failing to acknowledge that some of what you're publishing now already exists in a published form. You are not properly identifying your sources.
It differs because you are not misappropriating the work of others. But, if you regard your previous published work as the work of another person (which in existential terms it is!) then you will treat it correctly in the now. Refer to it and reference it as you would anyone else's work. Do that, and you won't go far wrong!!
Once I am writing a new research (article/book/chapter/dissertation/statistic/conference...) I remember sthg I wrote/published before, and find myself called to refer to, so it is better to use my previous publications as a reference than making self plagiarism, it is a way to guarantee the credibility of a scientific paper
"It is important to note that the standard process of publication in many journals includes ceding copyright of the finished paper to the publisher. While you are still the intellectual owner of the ideas and results, the publication is property of the journal. As such, reuse of that material without citation and/or permission is not acceptable. While this is counterintuitive, in the eyes of the law, reusing your own words is copyright infringement, even if you wrote them. Open access journals commonly use Creative Commons licenses allowing for reuse with attribution. In these cases, reuse of your own words is acceptable, but it is always necessary to cite the original publication."
All the published work we refer to is copyrighted to someone, unless the owner gives it up and it returns to the author. For that reason, I suppose that if we treat our own past publications as we treat the publications of others, isn't that good enough?
In my own opinion, if you were able to reference your already published papers in your current one as if you were citing another authors, i don't see anything scientifically wrong especially when the papers you cited were very relevant to the present paper to be published. When the percentage of you papers in your references were too much compare to other others, it becomes a crime.
Dr. Christopher Nock raised a fundamental question, and I am following that discussion. I recommend that you all take a look to the question that Dr. Nock suggested above: " You might find it useful also to follow the thread "For your own good, please reject RG's current offer on "Reads."
I do not think there is a scientific or ethical problem with this, especially if the quotation is within the percentage specified and accepted by the scientific sites and publishing journals.
What is plagiarism? Basically presenting ideas and content as your own even though it is not, presenting ideas and content without proper noting the original author or presenting the wrong author as the source of ideas or content. It basically comes all down to taking what is not yours and keeping your audience in the dark about the origins.
Who is the rightful owner? If ideas and content stem from previous works of yourself, it is you. Obviously. If I took some ideas of others and had to properly quote them, why should I not do the same with my own work? With my own content? Now there is the trouble. Lets' say in a previous publication you have come to some conclusions using the publications of other authors. In that book you properly quote those authors whose ideas assisted you. In your next publication you quote yourself, but since it has been the last publication in a long range of publications on the matter, you only quote that one and only yourself and don't point to the assisting authors you have referred to in the first publication. That way you camouflage where the ideas stem from and even though the reader of book no. 1 is being informed about the original sources, the reader of publication no. 2 is ignorant and believes it was you.
Technically speaking you could at least avoid that issue if you were to always quote the full range of authors even in successing publications. What else is there? Guideline no 11 of the aforementioned guidelines ask authors to refrain from writing an essay on a topic that is better been presented in a full scientific report. Well, thats' not very realistic. It is quite common to ask an author about a short essay about a specific problem. Naturally one would write a full book on a research but then take one aspect and turn it into an essay. If you fail to manage to deal with that problem within an essay you should not write it in the first place, but refrain to write an essay because you have already written about the topic elsewhere is unrealistic for a couple of reasons.
How often have you written a book or done research and realised that because of your chosen structure you are unable to dedicate as much energy to a specific sub-topic you have come across? A brilliant story from the past that sheds new light on the history of the student's movement of the early 1960es, but it quite does not fit in your report. You decide to mention it and present a very short overview. After your book is published a magazine or festschrift gets interested and asks for an essay focussing on that very topic you failed to present thoroughly in your book. "Oh no, thank you! I have already dealt with it in my book! I can't write about it now!" - You would not say something like that. You would jump at the chance and finally dedicate yourself to the sub-topic you have not had the chance to deal with in your previous research.
Is that plagiarism? Or self-plagiarism? Referring to Guideline no 11: aspects of research are sometimes better told within an essay than within a research. Also a magazine might want you to present a very short overview, referring to your previous research. You would do that for a couple of reasons. The most important probably to raise awareness of your research. People reading the essay might turn to your book too. Im sure your publisher will be very happy about that.
Then again there are people who re-publish one article over and over again. Researching on a specific topic I have come across one essay by a specific author that has been re-published at least three times (there might be more, but I found three). That is quite annoying, because you go to the library and either check the publication or copy it only to find out that you have read it before somewhere else. Then there are authors who use the same title for different essays published in different places. (That is plain stupid.) You think it is the same essay and don't check the other one, but they turn out to be completely different.
We could talk a lot about guidelines, but in my opinion it all comes down to this: you always should give full account of your sources and you should never keep your audience in the dark. If you have written on the topic, but in less detail, inform your reader about it. Tell him that you have already dealt with a topic in a book, that you have either dealt with it in more debth or that you failed to do so but are happy to be more elaborate in that essay. If you present a rough overview of your research, inform the reader about the publication where he could find all the details and do not forget to point to the authors of other publications that were decisive for your conclusions. In other words: "Don't keep your reader in the dark!" Do not sell off an idea as new that is not. Tell them that a certain idea stems from your previous book, don't leave them under the impression that your latest essay gives them the brandnew ideas they missed out elsewhere. There is nothing wrong with selling a second hand car, but it would be wrong to sell it as if it was brandnew.
Then there is the pressure of publishing a high number every year. That is what your university, your department wants you to do. Also number of quotations is being important (one of the aspects of RG you might want to question).
Self-plagiarism is for the author to "recycle" all or part of previously published content without citing sources. This practice may constitute an infringement of professional ethics in the case where the reused document or extracts have already been published because they do not respect the obligation to submit only original works. Self-plagiarism is not to be taken lightly! Self-plagiarism is one of the most disturbing cases of breach of scientific integrity. . If self-plagiarism is not theft from others, self-plagiarism deprives the reader of his fundamental right to access the origin of sources of the knowledge. Plagiarism and self-plagiarism: same sanctions.
Sorry, for another point: What about the experimental section, for example, we cannot change words from paper to another until the infinity ...! there are standard methods, techniques, using the same devices, the same procedures, etc...! Please, help us with your precious opinions, advices, experiences, .... Thank you in advance!
Recently I have received the similarity report on my manuscript. Most of the highlighted places (plagiarism) were concerned standard methods, techniques etc., (what was very surprised also our affiliation and acknowledgements). I have mailed to the Editor-in-chief and achived the answer like that: I understand what you are writing but I think that there are some other ways to say similar things and sometimes you can also refer to previous works.
We had to obligatory spent a lot of time to re-prashing the sentences used in previous papers. Honestly it was waste of time.
The question raised by Noureddine Ouerfelli, is also very curious for me. I totally agree with Khaled Muftah Elsherif, some sections definetly should not take in consideration of plagiarism.
@Noureddine, Thanks for raising that point concerning the methods section. One could still cite the previously used protocol, even if you authored it, and then explain briefly.