When there are a large number of "Missing" flags for a few students, it indicates the automatic video analysis could not detect the students face initially identified at the start of the recording. The students may not be missing, but the light or environment may have caused the students to appear as though they were in fact missing.

To produce a good webcam video, students should the following:

• Avoid wearing baseball caps or hats with brims
• Ensure your computer or tablet is on a firm surface (a desk or table) — not on your lap, a bed, or other surface that might move
• If using a built-in webcam, avoid tilting the screen after the webcam setup is complete
• Take the exam in a well-lit room and avoid backlighting, such as sitting with your back to a window

The article Respondus Monitor: Automated Video Analysis has additional details on how the process works and recommendations for students to provide high quality video.