Written by Dr Mary Davis, Academic Integrity Lead, Oxford Brookes Business School, Oxford Brookes University.
Scores can have false positives (text matches that are in fact ok or expected eg to the task rubric, cover sheet, a template, commonly used standard phrases, commonly used references or quotations). So high scores can sometimes consist of correctly cited work with many references (though may indicate some over-reliance on source text eg many quotations). High scores can also be due to matched text in appendices or if the submission is set up to exclude bibliography.
Scores can have false negatives (text matching does not indicate problems, but tutors can find problems with use of sources or authorship). So low scores can indicate plagiarism, little or no use of sources, and the use of custom writing services (which know how to avoid matches)
(Weber-Wulff, 2018)
(Weber-Wulff, 2018)
Sometimes it is necessary to use other forms of checking for copying, eg by putting a sentence into Google to look for matches.
(Weber-Wulff, 2018)
(Canzonetta, 2018 and Weber-Wulff, 2018)
(Williams & Davis, 2017)
http://stevebentleyhud.wordpress.com/2012/12/04/time-for-turnitin-to-get-rid-of-originality-percentage-scores/
(Davis and Morley, 2018)
• Use of white letters between words that look like spaces (download, select all, change all to red font)
• Replacing of letters like ‘e’ with a symbol that looks like ‘e’ (look out for inconsistencies in font shape)
• Use of different spelling systems (US/UK or other)
• Fabricating references and quotes (check authenticity of sources)
• Copying from old texts (eg books) with false references (as above)
• Use of translations from other languages/ online paraphrasing tools (check naturalness of language –this one may be hard to judge)
It is important to understand that the reason why there are multiple matches to other students’ work is usually because students in different institutions are using the same sources, writing about the same topics on similar programmes, and also that many academic phrases are used by students as standard ways of saying something in academic writing. The Turnitin database now has an enormous and continuously growing store of student work, so matches between students are extremely common as a result.
The email requests from Turnitin to share the student work contain the OBU student’s actual copied assignment under the message. Replying to these requests, even to refuse them, involves a further sharing of student work across email. There are thus issues of confidentiality in replying, and even more so in agreeing to share, for example, primary research details.
If there is a very significant match, there could be cause for concern, but rather than reply to the Turnitin request email, it is recommended that you contact the named staff member at their institution through finding their staff email.
References
Canzonetta, J. (2018). Can detection systems be used responsibly? In Student Plagiarism in Higher Education, Eds. Pecorari, D. and Shaw, P. in series Research in Higher Education, Abingdon: Routledge, pp.74-88.
Davis, M. and Morley, J. (2018). ‘How much can you copy?’ In Student Plagiarism in Higher Education, Eds. Pecorari, D. and Shaw, P. in series Research in Higher Education, Abingdon: Routledge, pp.28-46. https://www.routledge.com/Student-Plagiarism-in-Higher-Education-Reflections-on-Teaching-Practice/Pecorari-Shaw/p/book/9781138055162
Weber-Wulff, D. (2018). Why does plagiarism detection software not find all plagiarism? In Student Plagiarism in Higher Education, Eds. Pecorari, D. and Shaw, P. in series Research in Higher Education, Abingdon: Routledge, pp.62-73.
Williams, K., & Davis, M. (2017). Referencing and understanding plagiarism (2nd ed). London: Palgrave Macmillan. E-book available in OBU Library: https://www-dawsonera-com.oxfordbrookes.idm.oclc.org/abstract/9781137530721