Plagiarism is committed when one author uses another work (typically the work of another author) without permission, credit, or acknowledgment. Plagiarism takes different forms, from literal copying to paraphrasing the work of another.
The complainant must be made aware that the matter cannot be investigated unless at some point the journal editor informs the corresponding (or complained-about) author (due process).
The first stage must be a simple comparison of the relevant (two) texts. A simple side-by-side comparison by the editor for the simpler forms of plagiarism - a more thoughtful analysis by the editor if paraphrasing or types of ‘self-plagiarism’ are alleged.
What if the editor reasonably determines that there is significant overlap of text?
What if the corresponding/complained-about author accepts the position of the complainant?
What if the corresponding/complained-about author rejects the position of the complainant?
What if the corresponding/complained-about author has not responded in a timely fashion (approximately 30 days) to the editor’s correspondence?
What if the editor has decided to involve the employing institution or company, and if that institution or company responds and indicates they will investigate and mediate the result?
As with authorship or fraud complaints, what if an institution is contacted and responds negatively or does not respond?
What if a funding agency is involved?
What if the complainant and authors, or if relevant the employing institutions and funding agencies, fail to reach consensus or to act in a reasonable time?