Assessment in PBL

Previously I’ve written about problem based learning (PBL), and I did just finished another round with the heat problem in Physics 11.  A couple of issues have been revealed this year, and I’m not entirely sure what to do about them.

The first issue is one of differentiation.  This year I’ve had three classes try out the problem.  All three had 2 full periods to solve the problem, but very few groups actually finished the problem to the state where a solution was written up or sample calculations were done.  Those that did learn quicker didn’t need two full periods, while many could have used more.  I’m not sure how to best deal with this situation.  I suppose I could help the slower kids with more direct instruction but that really doesn’t make sense in terms of the pedagogy around PBL.  I could have required a finished solution worked out for homework, but this is sort of like punishing slower kids.  The homework assignment idea also has other issues around assessment which I’ll get to in a bit.  For the students that finished a quicker, I asked that they focus on their writing and citations, as these are valuable skills to practice.  However, this rings a bit hollow when they sense that it’s something “extra” because they finished first.

Assessing the PBL is another issue.  My instinct is to not mark the solutions.  Like last year, I’ve asked that everyone hand in their solutions and I leave feedback. But there’s not point in grading it - it doesn’t make sense to give a grade to work that is essentially their initial learning.  I’m not one for rewards and punishments though, so if I’m not grading it I don’t feel good about assigning it for homework.   So I’ve gotten the kids to do 2 periods of work, many don’t have a final solution, and my assessment of their progress is….  I don’t know.  And that’s a problem.

With proper backwards design, how a task or learning objective gets assessed should be planned before the assignment is given out.  In the case of this year’s heat PBL, I planned to read and assess their solutions.  With few solutions complete, it’s sort of a mess in this regard.

I’ve come up with a way to try and handle this situation, which addresses differentiation and assessment.  Students will have a choice of completing a short quiz on Heat (calculation thermal energy, specific heat) or submitting their solution. The problem solutions require a better understanding of the topics, whereas the short quiz is more accessible for everyone.  I stated above that it doesn’t make sense to grade the PBL, but if a student has done a really good job and hit the learning objectives, then it can make sense to use that as evidence of learning. With this plan comes a new issue: the solutions were worked on in groups  and grading individuals within group work is extremely difficult.

If you’ve tried some problem based learning, I’d like to hear how assessed the progress and learning.