What is the "Magic Number"?  There isn't one. At this point, you downloaded and read the paper. You determine that it might be publishable in your journal following revision. But before you fully advance it for external review, check to make sure that its wording has not been previously published by this author inappropriately (self-plagiarism) or by another author (plagiarism). If you do find a high level of similarity with just one source, see if that source was the author's dissertation or such. It is good practice to submit portions of one's dissertation or otherwise unpublished works to journals. So, focus on what is similar rather than a number. There may be instances where the author has used a quote and referenced the material appropriately or has used words from their own paper that has been published previously and been cited appropriately.



Interpreting the plagiarism checker requires a bit of deftness. You cannot simply look at the percentage of material found in other sources. Until you change the filter, for example, iThenticate will list items in the bibliography as well as ones found in other documents. And common phrases and even phrases in quotes may be included in that percentage of material found in other sources. If much of the material is taken from just one or two other sources, you should be alarmed. The point is, don’t rely on a single number. Focus on what was and was not found in other sources.

Figure 1. Interpreting plagiarism checkers requires discretion
It turns out that this paper was the author's dissertation. When this source was excluded, the similarity was 0%.

If you suspect plagiarism, place the submission On Hold and provide complete information about why you suspect plagiarism to the Executive Director. The Executive Director will investigate and report the results to the Board of Governors if warranted. We take plagiarism seriously. See Professional Misconduct.