This past term, I was teaching in a collaborative classroom where students sit together at round tables. This works well for in-class activities and peer learning, but is the not exactly the best configuration on the day of a midterm or final.

Concerned that some students might have wandering eyes – either inadvertently, or perhaps even intentionally – I came up with something that might help. Several of the exam questions required some basic arithmetic, so I made three different copies of the exam, where the numbers in the word problems varied a little bit. (Each version's problem was solved the same way, but the end result would be different.)

Later, I was talking with my daughter about what I had done. She asked me if I told the students that not everyone was getting the exact same test. (I had not.) She told me about some classes she had taken where the instructor had done this same thing, but announced it ahead of time (saying something like, "There's no sense trying to copy an answer from a neighbor, because the problems vary.") She also said that one instructor had gone so far as to print the exams on different colored sheets of paper. (My daughter assumed that all the orange tests were the same, all the blue tests were the same, etc., but that was just conjecture.)

If this makes any difference, there was already one cheating incident (or a class project) earlier in the term.

Also, I realize that it's often the "Show your work" part of an exam question that is the most important part, but that's not the case for this particular course. It's an introductory programming course, and I give small snippets of code, asking, "What does the output of this program look like?" So, for some of these questions, it would be very easy to copy an answer from another student's exam.

This made me wonder:

  • Am I under any obligation to share with my students the fact that there are multiple versions of the exam? Or is it okay to remain silent about the issue?
  • Is there any good reason for doing it one way or the other?
  • 23
    Presumably you would prefer for them to study and learn the material and take the test honestly, and not for them to cheat so that you can catch them. In which case there is a very good reason to tell them that cheating is not going to be a winning strategy.
    – ff524
    Aug 1 '16 at 22:00
  • 5
    Exactly as @ff524 says: there'll be vastly more impact (for people otherwise inclined) on study prior to the exam if you tell them well in advance of the difficulties that any prospective cheating will be more complicated. I'd avoid different colors, since that would make it easier to determine candidates for copying-from. Some years ago, I went to the trouble of writing a simple bit of software that would cycle through different-but-similar problems on cycles of 3, 5, 7 so that I could have 100+ exams that were not identical (but comparable work-load, comparable ideas). Aug 1 '16 at 22:03
  • 13
    I used to tell my students there were multiple versions of the exam when there was really only one.
    – user37208
    Aug 1 '16 at 22:21
  • 9
    @ff524 I am not completely convinced by the argument. If you tell them in advance, you only motivate dishonest students to find better methods of cheating. Instead, cheaters getting caught and punished may have more effect as a deterrent for future classes. Aug 2 '16 at 7:50
  • 8
    @J.R. I think the "good" (not-cheating) students are also annoyed by cheaters, and don't like that many instructors let them get away with it (by not taking any steps to mitigate cheating). They seem happy that I am trying to make sure everyone is on a level playing field.
    – ff524
    Aug 2 '16 at 17:42

At some point you need to tell the students. You do not want students leaving the exam and then talking about the answers and being totally confused. For example, it is not uncommon to hear a student ask after an exam, did you get 1 kg for problem 2. If the problems are different, this is going to make the discussions confusing and prevent the students from learning after the exam. Telling them on the way out of the exam room is often not feasible, so telling them in advance is probably better.

I would also suggest instead of slightly changing the questions, is probably not the best idea. It can lead to complaints that one exam was easier/harder than another. Further, if you provide solutions, it is much more difficult since you need to pair the solution to the exact problem. An alternative for reducing cheating is to mix up the order of the questions such that one student might get 1-2-3-4-5 and another gets 5-4-3-2-1. Then students can talk about the "train problem" and the "coin flipping problem" and not question 1 or question 2.

  • 12
    Apart from the potential waste of paper, for essentially algorithmic questions, a small extension of the software that puts together different exams can generate corresponding solutions... both to give to students and as an aid to whoever's grading. And the potential complaints that minor variations in data have a significant impact on "difficulty" is easy to dispatch in many ways... among them the presumed point that examples had already been done with varying data, and, anyway, why should a "5" make it harder than a "7"? In my experience, there are few such complaints, in part because... Aug 1 '16 at 22:41
  • 2
    ... the students [sic] who'd want to resist the difficulty of cheating are (in my experience) significantly intimidated by ... "technology". Aug 1 '16 at 22:41
  • 1
    I've done both. The software that generates the exams also numbers the solutions. Further, given the propensity of kids to sit in the same general area, in large-ish classes this makes it easier to return exams (not pinging all over the room). Further, the numbering indicates proximity during the exam, so evidence of cheating on adjacently-numbered exams is more damning than otherwise. For that matter, numbering exams even if the questions don't changes does give information that cheaters might be inhibited-by... Aug 1 '16 at 23:00
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    ... and, for detering cheaters, the insinuation that the instructor knows all the students, or has ways of tracking them, seems at least to mildly inhibit low-level cheating. I was "gratified" to have students tell me that they were "amazed" that I could match their name to their face... not to mention location in the room. ("Go me!") Well, duh, the obvious devices will enable this... and the students who are amazed deserve to worry about the effectiveness of their planned cheating schemes?!? That is, in fact, just creating a certain amount of "friction" can help ... deter?... students. Aug 1 '16 at 23:30
  • 1
    @J.R. The alternative view is that by doing some simple and obvious protocols to minimize cheating during an exam, it lowers students stress levels during test and eliminates distractions (at least when non-cheating students have had experiences in other classes where they feel that another student is 'cheating' but the instructor doesn't notice (or appears to ignore it).
    – Carol
    Aug 2 '16 at 15:04

Making different versions of the exam is standard practice in a lot universities when physical barriers against cheating are not available, when students take the test in different moments or with take away exams or homework.

Provided that difference of versions is not noticeable at first sight, not telling the students in advance won't harm honest students, but it will make dishonest students to unsuccessfully cheat in a way that will be easily noticeable - probably some students will produce the answer to their neighbours'questions. Therefore, I don't see an ethical problem in not telling them.

In the end it depends on what is your goal: If you want to catch dishonest students cheating, don't tell them, but if you prefer discouraging dishonest students from trying to cheat, tell them. When faced with that dilemma I usually choose the later.

Of course, by telling them you will give cheaters some useful information on how to cheat, but that should be addressed in another way.


A trick I have seen used, and plan to put in practise where suitable, is to make students use (parts of) a unique identifying number as the initial factor or exponent in the question.

For example, universities often have nine-digit student numbers which are ideal for being encoded in a computer science or mathematics question, especially where it is knowledge of a process or algorithm being tested, or the answers can be easily formulated from just the number provided the techniques applied are correct and accurate.

This allows students to study or even work together on an assignment/test, speaking generally about techniques and concepts that are relevant, without being able to directly share answers unless they do all the work together - in which case you have explicit collusion. In my experience this is a lot easier to find and a lot easier to penalise - because you can never quite judge whether Student A was exposing answers or Student B was copying without their knowledge, or that they had a system going, if they simply present the same answers from the same question.

  • 2
    Good idea, but I see two possible issues: 1) These numbers are sometimes meant to be confidential (especially towards other students), as they are used to semi-publicly indicate grades on bulletin boards. 2) If a student correctly solves the task with another student's number, wouldn't they still get most of the points? After all, the only factual mistake is a wrong initial value, everything else is a subsequent error. So, copying would only carry a minor penalty, only the points subtracted for picking the wrong initial value. Aug 2 '16 at 7:30
  • 3
    To 2. If the number you use doesn't even resemble the one listed on your paper's coversheet, you're immediately being called in for a frank discussion of the academic integrity policy, which the student signed to state adherence with. To 1. If another student can tie a number (not their own) to another student's identity, they're already in breach of any confidentiality and integrity policies that apply by their own hand, not of anybody else's.
    – Nij
    Aug 2 '16 at 8:40
  • 3
    I'd be more inclined to give each student a number I generated myself, rather than rely on, say, their student ID number. It might be a little more work, but it avoids a lot of potential complications, too.
    – J.R.
    Aug 2 '16 at 14:36
  • 5
    There was a case like this on a math test at Ohio State long ago. Distinguished senior professor was magnanimously teaching a large-lecture elementary course (math for poets kind of thing). He had students use digits from their student ID in the problems. This made all exams different. Then the lowly TAs had to grade the tests...they were up all night and still hadn't finished by the next morning. (Of course, this was in the days before personal computers.)
    – GEdgar
    Aug 2 '16 at 15:05
  • 2
    Don't use a student ID number if you're in a setting where exams are marked anonymously - because that means that the person marking the exam could know whose exam it is.
    – Flyto
    May 17 '18 at 13:18

(1) You are under no such obligation. (2a) If they know ahead of time, they will not even try. (2b) If they do not know, you will be able to directly detect copying-from-neighbours and have the offender punished.

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