So . . . my wife informed me that it is goal less, not goalless problems . . glad that is out of the way!
I have stolen them from Kelly O’Shea and have learned quite a bit . . .
First of all, I have decided not to use points . . . instead, I give a rubric grade on the three guiding questions at the top:
1. What is being modeled and how do you know?
2. Diagram / graph the scenario.
3. Find as many interesting quantities as you can from your graphs.
Students can get a 3/4 (on the 43210 rubric scale) on the first question, and then a 4 on the next two statements.
In order to have what I feel is a fair grading system, I give the students a formative assessment goal less problem, then we go over it the next day. Students tell me what they figured out, and when we are all done, I ask them to tell me what parts show advanced performance, then expected performance, then what would show incomplete performance, then minimal performance.
The students do a pretty good job of knowing what is advanced, and what should be expected.
I have also learned that if you expect students to do pie / LOL graphs, you better give them a picture for each graph!