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The CSC 151 photo quiz

This past week, I gave my favorite quiz in CSC 151. I call it the photo quiz. Students get a set of pictures of their classmates and have to identify them by first name. Now, I’m not cruel, so I provide them with a list of names. I’ve given a photo quiz in every section of CSC 151 for the past five years or so.

Why do I love this quiz? A few reasons. Giving the quiz reinforces some central concepts: the class is about more than the technical material; you learn better working with others, so you should work with a variety of other people; and you have awesome classmates, you should get to know them. My experience is also that students find this quiz a nice break from the weekly technical quizzes [1]. Finally, the quiz is a way for me to be sure that I know students’ names [2].

In addition, I always enjoy challenging the students to think about how I arrived at the ordering of pictures. The mechanism varies from semester to semester. Sometimes it’s more obvious than others. But it’s always an opportunity to get students to think about algorithms.

Of course, the quiz is not particularly accessible. Hence, we make accommodations as appropriate. We don’t require visually impaired students to take it, so it counts neither toward nor against their grade [3]. It’s also problematic for some students with learning or cognitive difference. We tend to make those accommodations on a case-by-case basis.

I admit that the quiz isn’t completely fair, even after I address those issues. Some students are better than others at faces. And some students have changed their appearance a lot since they had their class roster photos taken [4].

Figuring out when to give the quiz is sometimes a challenge. I like to give students enough time to get to know each other (and for me to get to know them). But I want it early enough that students clearly know each others’ names for a significant portion of the semester. Right before break seems like the best choice.

The quiz works well in CSC 151. Why don’t I use it in my upper-level CS classes? In part, it’s because CSC 151 is the only course in which I give a weekly quiz [8]. In part, it’s because students should know each other already in the upper-level classes. But our department has grown enough that students may not know each other as well. Maybe I can have them write not just names, but some significant fact about each classmate. I’ll have to think about it.


[1] There’s some quantitative evidence for that claim: The average score on the picture quiz is higher than it is on a standard quiz.

[2] Passing the quiz, even without the list of names, is no guarantee that I won’t still screw up names. In fact, it’s almost guaranteed that I’ll screw up names for the remainder of the semester. But the quiz is still a chance to know that if I sit down and think, I can identify every student.

[3] That’s not completely fair, since the average grade on the photo quiz is higher than the average grade on the other quizzes. We should probably come up with something more sensible. But I don’t think that skipping the picture quiz has ever negatively affected a student’s grade.

[4] The class roster photos generally come from DB [5]. Most DB photos are taken when students arrive on campus. They change hair lengths, styles, and colors. They grow or cut facial hair. They add or remove piercings. There also a host of other possible changes.

[5] Stalkernet, for Grinnellians of an earlier generation. If I recall correctly, the original version was written by the legendary Wayne Twitchell [6].

[6] I think Wayne wrote the original ProfQuotes, too [7].

[7] Neuroscientists are clearly multi-talented individuals.

[8] Given the evidence about the value of low-stakes testings, I wonder whether I should consider weekly quizzes in every class.


Version 1.0 released 2018-03-19.

Version 1.0.1 of 2018-03-20.