SBG Grain-size: Assess the Small, Evaluate the Large

One of the biggest changes to my assessment plan this year is that I intend to bundle standards in intro physics. See, one of the tensions that exists in competency-based grading is what grain-size of standards to use. Small-grain standards have the benefit of being very detailed and explicit about the concepts and skill students need to master. Two downsides are these however: Logistically, it can create a problem where you have TOO many standards. Learning-wise, it can create a problem where you’ve disassembled doing science into discrete skills so much that students aren’t really doing science anymore. Large-grain standards have the benefit of keeping the number of standards down (logistically) while also focusing on synthesis of skills (learning-wise). However, large-grain standards may leave students with feedback that is too broad and not targeted to the specific things they need to work.

Josh Gates, who blogs over at Newton’s Minions, approaches this problem by bundling fine-grained skills and concepts in broader competencies. Students receive feedback on the fine-grained skills and concepts, but competency at the synthesis level is what matters at the end. I am by no means saying this is the only solution or the best solution, but it has particularly affordances for my situation. Here’s why I think so:

• Since I don’t have control over curriculum coverage or pacing, I was always having to make compromises about which fine-grained standards were the most important to use. Students were getting practice and feedback on certain skills but not others. Even with this parsing down, I still felt bogged down by having too many standards. Simultaneously, I had too many standards and not enough standards. Re-packaging I think will help, because shifting my grain size up or down alone wasn’t going to help.

• Since 40% of the students’ grade is determined by high-stakes exams not written by me, the fine-grained standards I was using were helping to give students practice and feedback on underlying skills, but not enough on synthesis problem-solving. By bundling, I can make sure they are getting practice and feedback at the level they are expected to perform on exams, while also giving them feedback on the fine-grained stuff.

Here’s an example from Josh, and how he’s bundled skills skills into a competency that students understand the balanced-forces particle model.

I’ll be spending the next couple weeks revising and bundling my old standards to better support students learning and better align with the implicit curricular coverage established by the third-party exams.