Turnitin detection model guide
Turnitin's own description of how the model is trained, what the percentage means, which languages are covered and where it says the score should not be used alone.
What it is
This guide is where Turnitin writes down its own limits. It explains the sentence-level scoring, the minimum text length, the language coverage, and the reasons a score can be wrong. Anyone contesting a score should read it, because an institution's policy that goes beyond Turnitin's own stated confidence is easier to challenge.
When to use this entry
Use it as the primary source for what Turnitin itself claims and disclaims.
Questions
Does Turnitin claim its detector is proof?
No. The guide describes the score as an indicator that should start a conversation with the student.