Exams are an important component of the course grade in my courses, typically comprising 65-75% of students' overall scores. Most of the questions consist of multiple parts, some calling for calculations and many calling for interpretations and explanations. These questions are typically answered by a sentence or two, with a full paragraph expected occasionally. I almost never use multiple choice questions.

I do believe that exams provide an effective mechanism to assess students' knowledge of statistical concepts, ability to apply statistical methods, and skill at interpreting and communicate statistical findings. An important aspect of this for me is that exams given in a controlled environment are one way to assess the knowledge and ability of an individual student, as opposed to a homework or project assignment where students are encouraged to work collaboratively. While I am a proponent of collaborative learning and also supportive of making the development of teamwork skills a secondary goal of my courses, I do believe that it is important to assess students' individual abilities as well.

These are in-class, timed exams. I allot students as much time as the scheduling of the course permits. In other words, when I teach in 110-minute time slots, students can use the entire 110 minutes. When I teach in a 50-minute time slot, then students only have 50 minutes to complete the exam, and I try to rewrite the exam accordingly. On final exams students are welcome to use the entire 170 minutes scheduled for the exam. I expect all students who have studied well to finish the exam. My goal is for no students to work at a steady pace on the exam and run out of time. Typically more than half of my students are still in the room at the end of the class period, but I believe that the big majority are either checking their work or going back to work on questions that they found difficult.

To try to minimize student cheating, I prepare multiple versions of exams, with slight differences among them. I also copy these version on different colors of paper in an effort to discourage cheating just from students' knowledge that multiple versions exist.


I allow students to use their text and notes during exams. I think this helps to convey to students the message that the abilities to apply what they've learned and interpret statistical information and explain statistical reasoning are what I value and what I strive to assess them on. I do not want them to spend their study time memorizing formulas or reciting definitions. I also want to reward students who do a good job of taking and organizing their notes.

I strongly advise students that they should not regard my open book/notes policy as an excuse to study less diligently. In fact, I advise them to study just as seriously as they would for a closed-book exam, but of course the focus of their studying need not include memorization. I also advise students that in my experience they typically rely on their book and notes during the exam less than they would expect. A final piece of advice that I offer, and which most but not all of them heed, is that an exam strategy that advocates reading the book and trying to figure things out during the exam itself is almost surely doomed to dismal failure.


I encourage students to use a calculator on the exam; for some questions the calculator is essential. I typically do not allow them to use a computer, only because the classroom has half as many students as computers and I do not want to deal with the difficult logistical issues that would arise in trying to give every student equitable access to a computer during the exam. The only safeguard I take is not allowing students to share calculators during the exam. As students use computers frequently in the course, the technology aspect of the exam is not closely aligned with course instruction. I do include computer output on the exams, though, so students need to be familiar with it and able to interpret it well.
I strive to use real data, as opposed to hypothetical or realistic data, in exam questions. I can't honestly say that I start with a real problem, though. I usually start with the concept or technique or issue that I want to ask about, and then I find real data that can be used to assess students' knowledge of that issue.

I try to assign points to questions based on how many different components comprise the question. My aim is for at least 50% of the points to be based on conceptual understanding and interpretations as opposed to calculations and mechanics.


At this point in my career I usually start by looking at exams from previous years. I never re-use exams, but I do lift and revise selected questions. On the other hand, when I'm starting from scratch, I try to create a list of potential questions or issues while I'm teaching the course. Another strategy is that when I start to write the exam, I make a list of topics/issues that I want to ask about, and I try to put on that list several issues that students have struggled with in class or on homework. Then I start writing the questions themselves, and I try to find real data from other textbooks or from the Web in order to provide the contexts for the questions. Sometimes I'll even steal entire questions from the exercises of another text, but most often I do substantial tweaking of them. I usually write more questions than I'll be able to use, and then I look back over the exam to check for two things: a) whether I've "covered" the most important ideas, and b) whether I've included a reasonable variety of question types. I always aim to have at least half, preferably 2/3 or so, of the points on an exam pertain to students' conceptual understanding and interpretive ability, with no more than half on computational and mechanical skills. At this stage I often have to remind myself to include some fairly routine questions and not just challenging ones. Then when I think I have a reasonable exam draft written, I always ask a colleague to review it, commenting on whether it seems reasonable and suggesting ways to improve it. Then at the final stage I assign tentative point allocations to the questions. After the exam is given and graded, I evaluate it primarily by seeing how well students did on the questions that I consider the more challenging and conceptual ones. I'm most pleased if the best students give very good answers, the mediocre students give competent answers, and the less-prepared students struggle. I also look at the grade distribution and hope that the exam has succeeded in differentiating the students' performances. In a typical introductory course I hope for an average score in the low 80s, with several scores in the 90s, lots in the 80s, many in the 70s, and a few below that.

My grading system is more analytic than holistic. Students start at 0 points and earn points for k knowledge and abilities that they demonstrate. I assign partial credit for solutions that are partially correct and for demonstrating partial but flawed or incomplete understanding. Most frustrating to students is that I sometimes award less than full credit even when a mistake has not been made but because I find the quality of the explanation or communication lacking in some respect.

I am generally satisfied if the median score on an exam is in the low 80's. I rarely "curve" exam scores but do occasionally if the scores are particularly low or if I believe in hindsight that an exam was unusually difficult.

I try to make the total points equal 100 on an exam, which is equivalent to grading each exam on a percentage basis. I avoid assigning letter grades to individual exams, as I emphasize to students that it's the weighted average of their grade components that gets assigned a letter grade in the end. But I also tell students that they can do no worse than the letter grades based on a 90-80-70-60 scale.


I like to spend one class period reviewing for an exam. During this class period I typically present students with an "exam preparation handout" that contains an outline of the material covered on the exam and also suggestions for studying and for taking the exam. I spend some class time going through that outline with them, and I like to leave the remainder of the class period for answering questions from students who have already begin studying. I also usually have some questions and examples in mind to go over, based on areas where students have struggled, in case students do not have enough questions to last for the entire period. I do provide a review sheet to students, and I sometimes but not always provide additional review problems and solutions. Student participation in any review activities is optional.
I try to write helpful comments on students' exams, but I do less of this when I am teaching more than 100 students per term. I do usually post exam solutions on a website, and I encourage students to check those answers before coming to me with questions about why they did not receive more credit on a question. I do not spend much class time going over an exam, although I will spend some time addressing issues of common misunderstanding. Sometimes I tell students the fine-number summary of exam scores, but sometimes I just tell them the mean and median. I encourage students who do poorly on an exam to come and discuss it with me, but few do.