I have been making use of video exams for my classes. Details about them can be found here and here. This post will give folks some background on how I do the grading.

Quick Recap: This is what I did for the latest exam. I used the scores from the first exam, what I knew about the students, and other demographics to assign students into groups of three and four students. I gave the students roughly 48 hours to take the exam in their groups. Their exam deliverable is a 20 minute YouTube video of them working through the problems on their exam.

There were four questions. The first question was a quick concept one. (I had them explain a tiktok video – and of course they took it – ARGH – It was on YouTube too). The three other problems covered three types of questions that I hope the students could reason through. For each question, I developed 3 unique sets of numbers and assigned them to the various groups so each group got a unique exam. There were differences in the numbers that lead to different consequences for each scenario. For example in a given problem masses were arranged to lead to static friction whereas other scenarios it would lead kinetic friction. The exam difficulty was about two-to-three times a normal exam.

Solution Set: I did all three problems using the same formalism I teach in class. I compared the solutions next to one another and identified commonalities between the solutions. (Things I needed to check, e.g.,: is the block moving? How are the blocks constrained to move? etc.)

Rubric: For each problem, I created a list of core concepts/decisions that the students needed to apply/use in order to get the answer correct. (Simply having the correct answer isn’t enough.) I roughly assigned point values for each of these core concepts based on their relative importance. For example the use of units was often given 4 pts per person per problem. Folks who used units well got +4; whereas folks who were sloppy with their units might get +2.

After the test was graded, I went back and assessed if the student truly understood their work. I recognize there is an opportunity for me as an instructor to add bias to this unknowingly, so I gave it minimal points per problem (~5 pts problem). There were key things I listened for while I was watching the video such as “ownership” of the work. Again this was usually implemented in three steps. Fine – 0, hmm -2, This person doesn’t get it -5. Students will be happy to know that I watched their exams at X 1.5 speed.

As they were talking, I tried to note the time in the video when they said something that was unclear or lead to a loss of points. This way they can go back and review. I admitted got sloppier as I graded more exams. Ultimately my deliverable to them is a messy table with three columns for each problem. Column 1 is the time in the video, Column 2 is the issue, Column 3 is the points deducted.

I am not happy with the grading being a negative process i.e., I take points off. I much prefer it to be a positive activity where points are awarded for good work. However as it is a group take home exam, student’s work tends to be really good and it is just easier to take points off.