We are working on this feature, so here is my first attempt at describing the requirements.
In some of the large classes, we might have quite a few TAs grading an assignment. One way to divide them up is to assign several TAs to each part of the assignment. For example if we had 12 TAs grading an assignment we might put 4 of them on part 1, 4 on part 2, and 4 on part 3. The only mechanism we have in MarkUs to map graders to parts of an assignment is through rubric elements. So the idea is to assign TAs specific rubric elements and then use some UI features to highlight the rubric elements when a TA opens a student submission.
Assigning rubric elements to a grader is separate from assigning groups to a grader. A grader might mark one rubric element for all submissions, or might mark all rubric elements for a subset of the submissions, or might mark a subset of the rubric elements for a subset of the submissions.
I imagine a UI similar to the mapping of graders to groups or students. In this case we would see a list of the rubric elements with checkboxes (?) and would use much the same mechanism to map the graders to the rubric elements.
If the instructor does not specify rubric elements for a grader, then the default should be that the grader will mark all rubric elements.
After rubric elements have been assigned to a grader, when a grader view a submission, it should be clear which rubric elements they are supposed to mark. I am imagining that these rubric elements would be expanded by default, and would also be coloured differently. The graders should still be able to assign marks for other rubric elements, we just want the ones that they have been assigned to work on to stand out more.
As always, feedback and comments are welcome. What am I missing?