Plagiarism can not always be measured in percent. Habibzahdeh and Shashok (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160704/ differentiate between plagiarism in words and in ideas. It is obviousely difficult to decide the percentage of plagiated ideas. Bazdaric (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3284187/) cites some papers discussing 5 to 10% or 100 words. They present different tools and methods to detect plagiarism and discuss the importance of plagiarism in the diverse sections of a paper, giving more weight to the results and discussion section than material and methods.
In the case of standard protocol it is difficult to maintain uniqueness. There is less problems with Result section but in the case of introduction part and review articles, 10-15% is acceptable, with proper citation of references.
The matching text found is not an assessment of whether work has or has not been plagiarised. The plagiarism checkers can check the similarity index of the submitted paper and the suspect sources. Ideally the similarity index below 15% is acceptable but it depends upon the guidelines and the policies of specific conference/publisher/journals. Some authors also change the words a little or using synonyms but retaining the author's essential thoughts, sentence structure, and/or style without citing the source is still considered plagiarism. The Originality should be in the ideas and sense of honesty. Suggestion is also to check your papers on Licensed software or Copyright tools/websites, Freebies are not as authentic as Licensed/ copyright versions. Where ever have a doubt.......CITE.
As Dr. Marius Treutwein cited the Plagiarism can not always be measured in percent. Better to coin a sentence without changing the meaning / concept of any citation to avoid Plagiarism.
The research scientific committee of Pakistan allowed 15% plagiarism for Phd thesis but the good thesis or manuscript should be 100% or 3% free of plagiarism.
For review articles not more than 18 per cent
Less than 19 %
for good manuscript it should be 100% free from plagiarism
It can be any percentage 20, 30 , 40 but single paragraph should not be copied without the citation in references, bibliography. If full paragraph is taken for consideration it should be quoted.
Dear friend you can read this good article:
Syed Wali Peeran, Aisha Mojtaba Ahmed, Marei Hamed Mugrabi, and Syed Ali Peeran. Simple steps to avoid plagiarism and improve scientific writing. Libyan J Med. 2013; 8: 10.3402/ljm.v8i0.21825.Published online 2013 Jul 25. doi: 10.3402/ljm.v8i0.21825PMCID: PMC3724953
its a real problem, I think the softwares like for example iThenticate or others can give us a first information on how big or small in plagia.
Even you add references, but you must use your own words and sentences. I think many people forget this point.
The Editor and Reviewers have a to play an important role to decide whether the paper is publishable or not.
The acceptable percentage is around 20%. However, this percentage which is detected by plagiarism software (eg: turnitin) has to be revised by a specialist in the field to confirm the plagiarism. For example"cleft lip and palate" is shown by the software as plagiarism as the same four words are exactly used in many articles related to the subject. So the percentage of their repetition has to be deducted from the overall plagiarism percentage
Thank you so much, Dr. Iman. But how to deduct those particular words as most the plagiarism softwares has the option for continuous number of words and not the phrase which we need to deduct from the result.
Some of the plagiarism checkers include even the references / citations as plagiarism (similarity index percentage) which I believe is not acceptable. But, then how to detect if the article is copied or not and to what extent it has been copied? going by mere percentages does n't seem to be proper.
Firstly, there is no science to decide upon. In case if the content is copied it is better to mention about the source. There must be due credits to the respective author. Knowledge is not private but social property. As far as human cognition is concerned, It is highly impossible to get something out of nothing . We should feel happy living in a society where we still respect other's thoughts. If things goes like this, there is no wounder if someone file suite against other claiming that he/she thinks similar.
what about in Proposal? for example in Ph.D project proposal which part are considered to check plagiarism?
The review has to be easily understandable, well written and should provide correct & authentic information. Due credit has to be given to the originators of ideas and the work. To me percentages of words has no meaning. The use of language is to communicate and for this one has to use the best suitable vocabulary; some times others might have use the same words to communicate same or similar things. No doubt, review should not be repetition.
See this Wits Libguide for broad guidelines on Plagiarism (not a direct answer to your question, but you may find it useful)
Generally speaking, the percentage of similarity varies according to the algorithm used in the software such as, Turnitin, etc. However, in most cases the percentage varies between 5 and 20% as benchmark.
There is a very distinct difference between what Turnitin flags as matching text (aka: similarity index) and plagiarism. Turnitin will highlight ANY matching material in a paper—even if it is properly quoted and cited. Just because it appears as unoriginal does not mean it is plagiarized; it just means that the material matches something in the Turnitin databases.
Can any one answer the percentage plagiarism allowed under "publication" in a research paper?
most of the time it is between 5% up to 20 %
It is always based on the specific journal and specific reviewer. What Getachew provided is correct and reported in many places.
As per the software to check plagiarism, the range indicated above is alright. But better to keep % similarity around 3-5 percent which will be acceptable to all journals.
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