Copyright law protects unique authorship. When an author publishes work in an academic journal, he/she/they transfer the copyright to the publisher via contract.
The contract may guarantee that no part of the author's original work has been published elsewhere. Self-plagiarism is considered academic fraud.
Therefore, self-plagiarism violates publishers' copyright when it is a reproduction of their own documents to present them as new content. The distribution and sale rights belong to the intellectual property owner to whom the author has assigned the requests, per the contract.
The author may quote a small fragment of his work, leaving references. If he intends to mention a significant portion, doing so may be a breach of contract. It is a bad idea to cite several related paragraphs at a time. Moreover, it is even worse to substitute a citation with half of a new piece of work.
Many universities have databases of papers that students have previously submitted.
If similarities are found, the Academic Council will consider this evidence of the student's incompetence. After all, self-plagiarism:
- shows a lack of interest in creating a new, unique paper;
- means that the student does not contribute to science in a new way;
- undermines academic ethics and the public's confidence in science in general;
- violates the rights of publishers if the student's work has been previously published in a journal.
Abusing self-plagiarism can lead to expulsion or other academic sanctions.