When reviewing Bb Assignments with SafeAssign plagiarism enabled, Blackboard will provide an overall matching percentage for the assignment. This matching percentage is intended to show the instructor the percent chance that the paper contains matches to existing sources. For example, if a paper shows up with an overall matching percentage of 55%, SafeAssign is communicating that this paper has a 55% chance of containing plagiarized content.
The overall SafeAssign score is a warning indicator only - you will need to examine papers to determine whether the matches indicate plagiarism, or are appropriately cited. Here are Blackboard's recommendations for interpreting overall SafeAssign scores:
While reviewing papers, you will see highlighted portions of the paper's text. Click on a highlighted portion to view its sentence matching scores. Blackboard states in their published materials that these sentence matching scores represent the percentage probability that two phrases have the same meaning. This number reflects the reciprocal to the probability that these two phrases are similar by chance. For example, a score of 90 percent means that there is a 90 percent probability that these two phrases are the same. There is a 10 percent probability that they are similar by chance and not because the submitted paper includes content from the existing source - whether appropriately attributed or not.
Furthermore, SafeAssign ignores certain words and word combinations it considers common in order to avoid false-positives in its reporting. Because of this, it is possible for SafeAssign to report two matching blocks of text as less than 100% matching.