When multiple graders are grading simultaneously, it is possible that a grader will start grading their next ungraded submission (from their randomized list), only to find that, after grading, it has already been picked by another grader. (not the case when using assigned graders only).

To prevent multiple graders from grading the same submission simultaneously, introduce a claiming mechanism:

1. When a grader opens a grading form in edit mode, the system automatically tries to claim the submission for them.
2. If the claim is successful:
   • The submission is marked as claimed by the grader for 5 minutes. This is recorded in a server-side registry and displayed to the grader in the grading form.
   • A 5-minute timer starts on the client side. If the grader does not finish grading within this time, the claim info label or text is toggled to a link to reclaim the submission for grading. Clicking this link restarts the 5-minute timer.
   • When the grader finishes grading, the “graded” action removes the claim info from the server-side registry.
3. If the claim is unsuccessful, it means that another grader has already claimed the submission. The grader is presented with a modal or alert message suggesting that they navigate to the next ungraded submission. The grader may also discard the message and start grading, but they risk their grading data being overridden by the other grader.

Furthermore, limiting the claims held by someone to one would prevent a single grader to claim all ungraded submissions when just walking over the list of submissions.

Submitted by Elmer van Chastelet on 19 September 2023 at 14:24