Thursday, June 7, 2012

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.


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)


  1. I like this a lot, and have tried to do basically this, but fall of the rails quite a bit. A good reminder. He also points out that maybe they can give evidence in a different way; that policy has eased a lot of potential pain in my class as we went though the end of the semester.

    I'm also reminded of a partly tongue-in-cheek rubric that must be from Shawn Cornally or someone like that, and could be modified thus:

    4 - you've completely convinced me that you understand it
    3 - I think you understand it, but you haven't completely convinced me
    2 - I think you don't understand it, but you haven't convinced me
    1 - you've completely convinced me you don't understand it

  2. Well, this just saved me a lot of work! That simple change in perspective makes so much sense; I can't believe it never occurred to me before. It seems to me that kids might be able to spend more time coming up with their own understanding than trying to figure out what they think I want to see.

    Tim - I am definitely stealing your rubric :)

  3. @Jason this is a bit off topic, but can you tell me what you think about using grade weights with SBG? My school requires us to weight our grades. For example, homework is 35% and projects are 30% and tests are 20% etc. I absolutely hate it and I think that weights are incongruent with SBG. What do you think?