Grade passback is the mechanism by which a score or completion status generated inside an external tool — a video quiz, a simulation, a coding exercise — is written back into the LMS gradebook so that instructors and administrators see a unified view of learner performance. In the LTI ecosystem this is handled by the Assignment and Grade Services (AGS) component of LTI Advantage; in older LTI 1.1 deployments it used a simpler Basic Outcomes service. The LMS creates a grade line item when the assignment is configured, and the tool receives a line-item URL in the LTI launch message that it can later POST a result to. The result carries a score (a decimal 0–1), an optional comment, and a timestamp. For video-based assessments the practical challenge is deciding what constitutes the score: completion percentage, quiz score, a weighted combination, or a binary pass/fail. A common gotcha is that many LMS platforms cap the number of result updates per line item or cache results aggressively, so a tool that sends frequent incremental updates may find only the first or last result reflected in the gradebook. Testing grade passback end-to-end in the target LMS before release is therefore essential, as caching behaviour varies significantly across platforms.
