Hi venymae,

Thank you for your question! This has been a popular request for a while in Khan Academy and we are definitely taking a deeper look into this. That said, although Khan Academy does not currently have a diagnostic or assessment test, a workaround to this could be to have the student take the course challenge at the end of a course to possibly determine what skills they are already familiar with and what skills they may need to learn or relearn. However, course challenges cannot be assigned using the coach tools, so you will not be able to view their score from the teacher dashboard, only from the student's end.

I hope this helps! Please let me know if you have any further questions.