Burden of Proof

Brian Frank has a post where he talks about standards-based grading and evidence.

In a grading system where you take away points, evidence of misunderstanding and lack of evidence for understanding are both punishable offenses.  Standards-based grading, however, focuses our attention to confirming evidence of understanding.

I've had some recent posts stating that Argument is one of the pillars of science education. Here's where we get back to alignment. As Brian points out, one of the tenets of SBG is that the burden of proof rests with the students. Again to quote Brian:

The students isn’t punished for not labeling things the way you want them to; they simply can’t be given credit for understanding things for which they have provided no evidence. Maybe they will show that evidence later by labeling forces the way you want; or maybe they will show you evidence of understanding in a different way.

If we believe that one of the fundamental goals of science education, and indeed all education, is to teach students how to argue, then your grading system should align with that value.

I left a comment on Brian's blog with a link to this paper called Faculty Grading of Quantitative Problems: A Mismatch Between Values and Practice. This is by no means a rigorous academic paper but it has some points that are worth sharing.

If students are graded in a way that places the burden of proof on the instructor (as 47% of the earth science and chemistry faculty did), they will likely receive more points if they do not expose much of their reasoning and allow the instructor to instead project his/her understanding onto the solution. On the other hand, if they are graded in a way that places the burden of proof on the student to either demonstrate his/her understanding or produce a scientific argument, they will receive very few points unless they show their reasoning. Most instructors tell students that they want to see reasoning in problem solutions, however students quickly learn about an instructor’s real orientation towards grading by comparing their graded assignments with those of their classmates, or by comparing their own grades from one assignment to the next.

I love this idea of burden of proof. If we place the burden on the teacher, we need to interpret what the student means and students are encouraged to leave out reasoning because that might end up deducting points. I'm reminded of Scott McCloud's concept of closure in comics. We end up filling in the blanks between panels.¹

If we place the burden on the student, the answer is simple. Why do you need to label forces in this way? I don't know if you know it until you show me.









1: I'm talking reasoning and argument here. Don't even get me started on the massive equity issues students confront when we fill in the blanks.




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I've also got another post up at ASCD Inservice. This one is based on a Robyn Jackson seminar and is a small modification I'm making on teaching compare and contrast. It's on increasing rigor and if I'm going to stay on topic I'd say students will need to understand and negotiate with what constitutes acceptable proof of understanding. That is, if all I do is give students pre-written tests, I've placed a ceiling on what my students understand of proof. (Full disclosure: I get paid for these posts)