Rubric for assignment with optional parts?

[JonBerry]

I think I may have rubricked myself into a corner...

I assigned a group project. Some groups have 3 members, some groups have 4 members. All components  of the project are required for groups with 4 members, but certain parts are optional for the 3-member groups (essentially turning the optional stuff into extension activities). 

Is there a way to excuse parts of a rubric for groups that don't do the optional parts so they're not penalized? Should I just give them full credit for those parts? Do I create separate assignments for 3- and 4-person groups?

Also, the groups with 4 students instead of 3... The 4th person is pretty much dead weight. I was trying to spread the load so that it didn't fall on just 1 or 2 students to make up for their missing group members

[Hildi_Pardo]

Hmmm.  That is a tough one. 

This may not resolve your issue, but could still be helpful.   To make a rubric with an extension (or "extra credit") you can make the rubric have a greater value than the Assignment's points.    In other words, let's say there are three required criteria, and an extension/extra credit criteria.  The three required have a value of 5 points each, and the extension has a value of 2 points.   That's a total of 17 points, 15 of which are for the required components.  So you set the Assignment to 15 points -- then if they earn the points for the optional work, they'll earn two additional points.

[KarolMurphy]

Hildi,

That might work for some scenarios, I feel like I have come across similar scenarios to Jon, with the rubric and would love to find a solution.

1. Exam with 6 questions, each worth 20 marks, pick the best 5. Rubric can award over 100
2. Assignment with 20 criteria, each worth 5, but some elements are optional. Say a response has 2 n/a, I would like to grade out of 90 rather than 100.

Any ideas for these scenarios?

[AbigailTamkin]

If it's optional, does that mean that any points they earn for those parts are extra credit? You could make an item in your rubric worth zero points, then type in the appropriate point value when grading.

If it's going to be out of a different number of points, then that sounds like a different assignment with different rubric?