Symptom

Student submits paper once, revises, then submits again. Originality Index of the revised paper is higher than the original paper.

Cause

Most likely, Turnitin is comparing the revised paper to the initial submission.

This happens because:

• (in Turnitin - direct or IVLE) the instructor:
  
  • did not change the Optional Settings to Generate Originality Reports for student submissions... immediately (can overwrite until due date), and/or
  • required the students to submit drafts to earlier Turnitin submission folder(s) and did not change the Optional Settings to Submissions to this assignment will be stored in... do not store the submitted papers.
    
    
• (in Quick Submit - staff only) the staff checked the Add file to Turnitin's repository option.
  • Once a file is added to Turnitin's repository, the submission of a revised paper is checked against the earlier submission.

Solution

Staff can exclude the source(s) leading to the skewed Originality Index.

Finally, please configure these settings if you have not done so:

• In Assignment Settings, expand Optional Settings, then choose Generate Originality Reports for student submissions immediately (can overwrite until due date).
• For Submissions to this assignment will be stored in..., select Do not store the submitted papers.