A few weeks ago, I created and tested a single-use, scratch-off mini-case study for my parasitology class. The students absolutely loved the idea, and as I watched them work, it became clear that this could be an incredibly effective tool.

Using scratch-offs isn’t exactly a new idea, and the approach comes with several benefits. First, scratch-offs give students immediate feedback. If they get an answer wrong, they must continue to work on the problem until they get the right answer.

Second, something about scratch-offs is inherently more engaging than a clicker quiz, even though they are functionally similar. With scratchers, you use every resource and debate every option to get the correct answer and keep the “perfect” card. Suspense builds as you scratch to reveal hidden knowledge, especially if you are working against the clock. You feel empowered when the correct answer is revealed and double your efforts when you’re wrong. Don’t get me wrong, digital classroom response systems are still excellent, effective, and easy tools, but the occasional scratcher mini-case creates engagement that excites.

Creating a Mini-Case Study

Designing these mini-cases can be a substantial time investment, but once the design is completed, printing and assembling the scratchers only takes about 15-minutes of prep time for my class of 70 students.

Templates

Materials (~$0.06/card)

Space is limited on the card, so keep it simple. Include enough details so the students can diagnose the patient, such as clinical signs and symptoms, microscope images, patient behaviors, location, and other risk factors. If you are going to include images directly to the card, you’ll only be able to fit 50-100 words on my template. If you need to add more details, you can free up space by projecting images using PowerPoint.

After you write the case, pick nine possible answers, randomize their order, and arrange them in the 3×3 table on the scratch-off sticker template. Font size 7 seems to work the best with my template, but you may have to abbreviate or use a smaller font on some long scientific names. I print the stickers on my office printer (Lexmark MC2425) and it usually works smoothly.

Copy and paste your scratch-off answers into the table on the card back. Add “correct” or “incorrect” under the scientific name and add a strikethrough on incorrect answers. Once you’ve printed the back, put the scratch-off sticker over the answers, separate the cards, and you’re ready to go.

Game Day

I pass out the cards before class and give the students the first two minutes of class to solve the case. I almost always throw some sort of secondary challenge on the back; for example, describe the life cycle, draw the infectious and/or diagnostic stages and label important structures, a second scratch-off case, or using the chain of infection to describe three ways to prevent the spread of the parasite.

I’m still designing and testing the game aspects of this exercise. Teams are scored using golf rules, earning one “stroke” for each square they scratch. If a team does not turn in a card, they earn the maximum score for that card. Scores are updated and tracked using keepthescore.co. The game component of this won’t be implemented until the Spring of 2023, so I’ll create an update post later.

My Scratch-Offs

I started creating these mini-cases towards the end of the 2022 Spring semester. I’m not teaching this class again until the Spring of 2023, so there likely won’t be a complete set for parasitology until then, but you can download and print my scratchers here.

Student Feedback

Student feedback has been overwhelmingly positive towards this exercise. We’ve tested multiple formats for the exercise (individuals, pairs, and small groups). My students preferred to work in pairs or groups of three (which also helps cut down costs and prep time).

Attribution and Usage

This content (including the individual cases) is published under the Creative Commons Attribution-NonCommercial 3.0 Unported

You are free to share and adapt this material, but you must provide attribution. This material may not be used for commercial purposes