SafeAssign and AI detection
SafeAssign is a similarity checker. Similarity and AI detection are different measurements, and confusing them is the most common mistake made about Blackboard reports.
SafeAssign is Blackboard's originality tool, and the thing worth knowing first is what it was built to do: match your submission against a database and report overlap.
That is a lookup. It finds text that appears somewhere else and shows you where.
Similarity is not AI detection
The two measurements answer completely different questions and they fail in completely different ways.
Similarity asks whether your text appears elsewhere. It matches, so every result comes with a source you can open and check. A high similarity score points at something.
AI detection asks whether your text has the statistical properties of generated writing. It matches nothing. There is no source, because nothing was found. It is a classifier's probability and it comes with an error rate rather than a citation.
Generated text is usually original, so it produces a low similarity score. That is the part that catches people out: a clean similarity report says nothing at all about whether a classifier would flag the same document.
What that means for a Blackboard submission
If your institution runs SafeAssign, you are getting an overlap measurement. Whether an AI indicator also runs depends on what else your institution has enabled, frequently Turnitin alongside it or through a different assignment type, and that is a per-institution configuration we are not the right people to describe.
Worth checking which report you are actually looking at before drawing a conclusion from it.
If an AI indicator is running
It reads the same properties every detector reads, because they are properties of the text rather than of the vendor: predictable word choice, and sentence lengths that stay close to each other.
Turnitin publishes how often that goes wrong on genuine human writing: 4%. Ours is 0.4%, which is 99.6% specificity, measured on 15,900 documents of real academic writing.
The writing most exposed is formal, evenly paced and heavily revised, which is most academic writing. Our corpus puts human academic prose at a within-document sentence-length standard deviation of 8.7 words against 6.4 for generated text, and every editing pass moves a document toward the lower figure. See why AI detectors flag human writing.
Checking before you submit
You generally cannot run either tool on your own work outside a submission, and if a draft area exists it shows similarity rather than an AI indicator.
What you can do is score the document per paragraph yourself and see which passages read flat.
Ours is free and unlimited with no account, takes .pdf, .docx and .tex, has no word cap, scores every paragraph separately, and never stores your text.