I have a professor who administers tests where students have to answer 6 out of 10 short answer questions. He has done so by setting up an assignment with a rubric whereby students upload their submission (it's a take-home test) and then he only fills out the rubric columns for the questions the students answered (hence, there are 10 rubric criteria - one for each question - but only 6 of them will be filled out based on what the student chose to answer).
This works well enough for his purposes, but he would also like to be able to export data about the rubric to see where his students did well and not so well. I know that this isn't yet available for rubrics (c.f. Export aggregate rubric scores to identify strengths and weaknesses of class as a whole), but I thought that if he could set up a quiz whereby his students only answer 6 out of 10 questions he could use the more robust quiz data tools to accomplish this.
Unfortunately, I can't find a way to set up a quiz such that the system knows students only have to answer a subset of the questions given. Am I missing something, or does anyone have a good workaround to create something like this? (It's a pretty basic function of testing - in my humanities undergrad I rarely took a test where I didn't have at least some choice in what questions I answered.)