Turnitin Similarity is a plagiarism tool that allows you to have submitted work checked for plagiarism.
NB: This is only a tool. If you suspect a case of plagiarism, contact the assessment/exam board.
With this tool, as a teacher, I can:
view the plagiarism score via SpeedGrader in Canvas;
view a comprehensive plagiarism report;
Turnitin Similarity gives you the option to include or exclude certain search sources and/or parts of a submission when creating the plagiarism report.
Pay attention to the following
The tool is integrated into Canvas and can only be linked to assignment submissions in Canvas.
You cannot apply plagiarism check to submissions after the fact. Make sure you set this in the assignment settings in Canvas.
When does this tool work best?
Do not draw quick conclusions based on the plagiarism reports. For an efficient plagiarism check, think in advance about how to avoid high erroneous scores: ask students not to copy the questions, etc.
It may help to first familiarise yourself with Turnitin Similarity methodology before studying the plagiarism reports. You can find this in the manual through Canvas.