My Design for Organic ExamsOctober 21st, 2014
It’s fall semester at SLU, and I’m teaching organic chemistry for our majors once again. Last year, I was focused on just getting through the course. I was so consumed by producing slides, homework assignments, practice exams, and real exams on a tight schedule that I didn’t get to think hard about the finer points of design until the class was over. Now, on the second pass, I can focus on making improvements rather than creating everything from scratch.
At SLU, instructors don’t get assigned TAs for proctoring and grading unless the class has greater than 30 students. In the spring, the majors’ class fell below this number and I had to think about designing exams to make grading as efficient as possible without eroding their effectiveness as tools for teaching and thoughtful evaluation. The system I settled on was different from my experience in both college and grad school, so I thought I’d share.
I’ve settled into a system in which quizzes and exams generally have four or five sections/problems picked from the following varieties: multiple choice, mechanism, synthesis, A+B reactions, explanations, and calculations. While I’ve never been a huge fan of multiple choice, it allows me to test a variety of straightforward points without the strain of having to grade a wide assortment of free-response questions. My multiple-choice questions are typically five choices, with students getting +5 points for a correct response and +2 points for leaving a question intentionally blank. This scoring system introduces a penalty for guessing; students need to recognize that sometimes the best option in life is to admit “I don’t know.”
In my system, if there is an exam on Wednesday, the students have a quiz due on the previous Friday that covers the same material. Each quiz contributes 2% to the final grade in the course, while each exam contributes 20%. The quiz has the same length, format, and answer sheet as the exam, except the problems are harder to compensate for the fact that I give students 48 hours for the quiz and allow them to talk with each other about the answers. I like how this approach requires the class to be familiar with the exam material almost a full week before the exam, and that students have an incentive to form study groups and debate answers to hard problems. I never learned as much in organic chemistry as when I was trying to defend my proposed answers to classmates. Finally, having what is essentially a hard practice exam due on the Friday before the “real” exam means that I can return it graded and marked with comments by Monday. In many cases, these quizzes serve as wake-up calls to students while there is still time to fix issues that need attention.
In every chemistry class I’ve taken, students either wrote their exam answers directly on the problem booklet or in small blue exam books. I find these response media are murder to grade because you spend so much time flipping through pages, hunting for answers, and flipping back to write the subtotal for that problem on the cover page. And, of course, there are always two or three students who get creative and write their answers out of order or on the back side of pages.
To solve this problem, I started writing exams such that students have to place all of their answers on a single letter-sized piece of paper. I draft an answer sheet for each exam on which it is clear where each answer should be written. When the answer is a single word or structure, I’ll typically draw a box for it. The use of a single sheet minimizes the burden of flipping, while the answer boxes (located at the same spot for every student) minimize the burden of hunting. Here’s a sample answer sheet typical of one of my orgo exams:
I copy answer sheets onto 65-lb. card stock so that both sides of the sheet can be used without the pen ink bleeding through to the other side. I find that the smooth sheets sold under the Neenah brand are better than sheets of the less expensive Staples brand, which have an annoying coarse texture on one side. The card stock also gives a regal quality to the answer sheets. These puppies are suitable for framing and will withstand decades of wear if pinned to the refrigerator door of a proud parent.
Another nice thing about having students limit their answers to a single sheet is that the entire stack for the class can be scanned without hassle. Most modern office copiers are capable of sheet-feed scanning, so if your exams have no staples, you can scan the entire stack of paper all at once and e-mail the data to yourself as a single PDF. What a wonderful miracle of technology.
I scan the entire set of answer sheets both before and after I’ve graded them. In doing so, I have a permanent record of performance that I can access for eternity. If there is an issue over improper grading or a student attempting to cheat by altering answers upon return of the graded copy, I can refer to the electronic file. If a student needs a letter of recommendation two years down the road, I can open up the file and make specific comments about his/her performance. And if I want to mine data in the future for some pedagogical purpose or project, all of the data will be available for analysis.
A final important feature of each answer sheet is that I have a line for students to write their names at the top of the back side. This makes returning exams very simple, because I can fan them in columns in alphabetical order on a table and have students come in groups to pick them up. With only the top inch of the back page of each sheet exposed, students cannot see each other’s grades. Of course, as the columns thin out, I adjust the sheets to prevent greater exposure.
As I discussed before, I allow students to bring handwritten notes into exams. They serve to emphasize that organic chemistry is about analysis—not memorization. Also, having students organize the information of each unit onto a single sheet of paper forces them to make connections about the material in their minds ahead of the exam. This semester, I’ve started collecting, scanning, and returning these note sheets as well. I am fascinated at how students organize their thoughts, and I plan to use this information in my future letters of recommendation when appropriate. How an individual organizes her thoughts on paper gives you an interesting window into her mind.
So, that’s the system. Are there drawbacks? Yes. I tend not to write long mechanisms or synthesis problems that go over four steps, because there isn’t enough space to do so. With that said, I’m not sure if these problems offer much added benefit relative to alternatives with more concise answers.
One thing that I’ve found surprising is that even though the answers for the exam all fit on one page, there are students who still feel they need three hours to finish. I thought that offering four shorter exams instead of three longer ones would make time a non-factor, but often at the end of two hours, I still find myself nagging for all of the papers to be turned in.
Anyway, I like how this system works and will continue to modify it to work better for both the students and me. It is ironic that as a teacher, I feel that I am the one in the classroom who has the most to learn.