Turnitin is text matching software that is used to help understand the originality of work submitted for assessment.
While Turnitin can highlight issues with plagiarism, that is not what is shown in the report.
How Turnitin works
Every time work is submitted to Turnitin, it will be compared to other material which already exists on the database. Turnitin stores a database of sources which includes journals and books, internet materials and work that has been uploaded to Turnitin globally.
If the text submitted to Turnitin matches other sources already entered the database, it will be highlighted on Turnitin. It is normal to have at least some text matching in Turnitin. This does not always mean plagiarism has occurred, and the report will be interpreted by the marker.
After submitting work to Turnitin, a similarity report will be produced. The similarity report gives information about the text which has been matched against another entry in the database and will produce a percentage, as well as highlight sections of text.
The report needs to be carefully interpreted to understand if plagiarism has occurred. Chunks of extensive highlighted text will need to be investigated as this may mean that more careful paraphrasing is needed.
Turnitin may highlight assignment titles, commonly used assignment forms, reference lists or bibliographies, and quotes which use single quotation marks.
Read more about interpreting the similarity report.
Types of matches you may see in Turnitin
Quotation and reference lists
In a paper which has relied heavily on quotations, the similarity score will be high. Quotes can be excluded from the similarity report, provided you have not used single quotation marks. Turnitin does not recognise single quotation marks.
Depending on the settings, the reference list or bibliography may also be highlighted. This can be adjusted in the settings.
Large chunks of highlighted text highlighted in a single colour
If there are large chunks of text that are completely highlighted in one colour, this indicates that the material matches another source which exists on Turnitin’s database. This will need to be looked at more closely.
Chunks of text highlighted in multiple colours
This indicates that a number of sources have been used within the writing, but this has not been paraphrased correctly.
Scattered sections of highlighted text
This happens when large chunks of text have been copied, and while there has been an attempt to paraphrase, this has not been done completely.
Turnitin will pick up small matches, so it is important to check the settings and be aware of this. Things like course names, assignment declarations, lecturer titles, and matches of 3 words or more may be highlighted in the report as they will have entries on the database. By carefully reviewing the report, it is possible to identify what is problematic, and what is ‘noise’. The settings can also be adjusted to not highlight these.