Are you noticing a higher amount of invalid tests this fall? Students who have rapidly guessed for 30% or more of the test will have their test invalidated and will need to retest. It's important that proctors are aware of the disengagement alert on their console so that they can intervene before the test becomes invalid. See FAQ: Rapid-guessing, disengagement, and invalidated tests for more information and how to identify these invalid tests in reports.
We have a current discussion about this topic in our Professional Learning Online space if you would like to participate and read the blog posted by one of our researchers at NWEA.