Q. Can you plagiarise yourself?

Yes. Self-plagiarism is when you reproduce your own prior work without citation, passing it off as new original work.

Self-plagiarism is poor academic practice and may be a form of academic misconduct or fraud under University regulations, which could result in disciplinary action being taken. However, repeating jargon or turns of phrase which are commonly understood in your field of study is normal, and is nothing to worry about. Likewise, if you are reusing underpinning data or concepts from prior work in a new work, there may be a certain degree of similarity or overlap.

If you are building on your prior work, to avoid self-plagiarism, it's important to acknowledge it correctly. You can do so simply by following the same citation and referencing conventions that you would use for any other work. This is called self-citation.

If you're a doctoral researcher and are publishing work based on your thesis research it might appear that your thesis has 'plagiarised' your publications or conversely that the publication has 'plagiarised' your thesis.  Again, it is important not to panic, but to avoid this, you should:

• ensure that all citations and quotations are correctly acknowledged, e.g. using quotation marks, bibliographies and clear in text citations to the prior work. 
• for work also being published, you should disclose to your publisher that the work being published is based on doctoral research and that the final thesis will be archived in the University's open access repository, BURA and under national sector agreement with universities, in the British Library national collection of UK thesis research, EThOS. 

The thesis and any publications arising from the thesis research, will each have separate copyright protection, unless they are substantially identical. 

For further information, and related topics, see the links below.