Abstract: As a TA for advanced undergraduate physics labs, I had to mark (“grade” in American) a lot of lab reports last quarter. Being a slow and poorly motivated marker, while wanting to give good feedback to my students, means I dreaded this process every week. I figured it would be improved, or at least quickened, if I went to a coffeeshop to remove distraction, and drank caffeinated beverages while there, both because that is part of societal expectations for what one does at coffeeshops, and also to improve focus. Preliminary experiments showed this to be a terrible idea. I still went ahead and repeated the experiment two more times. Now there is a conclusive set of data to be able to say with great certainty that it is, indeed, a terrible idea.
Apparatus and Procedure:
To perform the experiment, the only materials used were a stack of labs to be marked (Fig. 1) and coffee and tea drinks of various kinds (Fig. 2). The initial experiment was performed at Ballard Coffee Works. All subsequent investigation was performed at the Bauhaus.
Data Analysis and Discussion: The overall amount of time taken per lab fluctuates by over a factor of 2 during 6 hours, with a clear minimum at around the 3.5 -4 hour mark (Fig. 3). Frustratingly, as you approach the minimum, you continue to hope for a further speed-up in marking. However, the per-paper time quickly begins to rise, ending up even worse than initial times.
Upon closer investiagation, it becomes apparent that this is caused by actual marking time to be dependent on two separate factors, which scale with time spent in the coffeeshop in opposite ways (see Fig. 4). A third factor is also identified (see Fig. 5), and although it does not significantly affect marking times within the 6 hour window, I theorize that it would come into play in the 7th hour. Further investigation of this point may be taken up in the future, if I am ever dumb enough to do something like this again.
Finally, I noted a pernicious change in attitude that occurred as the marking went on. Whereas during the first hour, I was accepting of half-there answers and tried to interpret to the students’ benefit, I seemed to develop some kind of unshakeable resentment against the students towards the latter part of the exercise. I would start to feel glee whenever someone screwed something up terribly, and deducting marks started being fun. Thus, after the 4th hour, students face a double penalty of both the marker’s inattentiveness, and their malice. This is an effect that needs to be (and was, to the best of my abilities) corrected for in order to ensure fair results to students.
Conclusion: Marking labs is awful. Drinking caffeinated beverages for six hours straight is crazy. Combining the two doesn’t make either of them better.