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Dealing with Plagiarism

Karen Lang

Plagiarism has turned out to be a major problem this year in my Computer Science class. I have had five separate situations where I caught students handing in copied code. I seem to be the only teacher in our building (there are only seven of us) that had any issues with plagiarism this year. I wondered, "Why me?" Is it that my course is so difficult that students must turn to copying? Is it that I read my students' code so closely that I am able to catch these duplicates?

Carolyn Duffy Marsan, in her article in NetworkWorld contends that students in CS don't necessarily plagiarize more. It is just that CS teachers are able to catch them due to access to automated tools. I didn't use any software. I just used good old detective work. It wasn't too tough to catch, frankly. One student's use of odd variable names or a unique indentation of code, when replicated, jumped off the screen with a big red flag.

All copying occurred between students, not from online resources. I encourage collaboration between groups so students are allowed to ask other students for help. However, I draw the line with transferring of files. Students try to wiggle out of the infraction on that technicality, stating that they sat next to each other and programmed together, or one showed the other what he/she had done, while the other sat and typed.

I could use the approach that Georgia Tech uses, according to the article. They allow students to copy, in order to encourage collaboration, as long as the students can demonstrate their understanding of the code. Assessments count for more than homework assignments.

Plagiarism is a problem in this day and age of information at your fingertips. Technology makes it very easy to copy and call it your own. Students have such a cavalier attitude about copying and using music, video, and software without paying for it. Is that different than handing in an assignment for a grade, without working for it?

I experience disappointment and anger when plagiarism situations arise. And I am not naive enough to think that I found every copied piece of work this year. I look on the ones I do find as a teachable moment and see it as a good early warning to students before they get to college and beyond where it can have much large consequences.

Do you have plagiarism issues in your classroom?

How do you handle it? What do you do to prevent it?

Karen Lang
CSTA Board of Directors


I have always encouraged constructive collaboration because this is a relevant skill for the "real" world workplace, and it is inevitable given the climate in most classrooms.

We distinguish formative from summative assessments; the later is assigned greater weight in grade calculation and cannot be re-assessed. Code is formatively assessed---it can and should be edited as improvements are made. The final submission of any assignment, however, requires documentation and unit-tests. These are summative assessments. I look for preconditions, postconditions, and invariants here. Verbatim copying of anyone else's words are now more easily discovered and are actionable under the current understanding of academic integrity: so it is easier to make the case.

The unsettling undercurrent in these discussions, for me anyway, is the tacit expectation among students and their parents that this kind of behavior is not only acceptable, but is laudable.
And yes, we can debate the origins and nature, but at the end of the day, I fear that we will find that education has been reduced to a "commodity," thanks to the NCLB misguided, mean spirited, and unfounded focus on "standards" and "data" as the "products" of education. Naturally, this is just the carte blanche that parents and students use in those rare confrontations with the Administration who, being politically motivated, frequently side with the defendants.

Good luck with this one.


Disclaimer: I'm a university instructor, so the issues here are different than for high school instructors.

Yes, I have plagiarism issues ... lately, roughly one a term in my data structures course. Usually, I find them because of the MOSS detection tool, which is invaluable to me.

There were terms that I had more of them ... until the word got around that I was checking, and exacting a substantial penalty. It still happens, but usually it's an act of last-minute desperation rather than a deliberate decision to systematically deceive.

There's not a whole lot I can do to prevent it ahead of time. Sure, I try to rotate assignments, develop new assignments, and so on. But there are only so many new ideas in the world. My worst week as an instructor occurred a couple of years ago in my advanced algorithms courses where I came up with a "original" assignment, and half my class found sources on the web for the problem that I didn't even know existed.

The first offense can result in anything between half-credit for the assignment to a zero, depending on the nature of the offense. With the way I structure my course, this translates to a 1/2-1 letter grade drop in their final course grade. On the rare occasions I've had a second offense, the student fails ... not necessarily because of the penalty, but usually because the student hasn't been able to earn enough points on any other assignments/exams to pass anyways. Most often, the student tends to drop the course before that second incident.

I know that students enrolled in my computer class are copying code. It is obvious when the code cannot be reproduced on a test. It was also obvious today when I was doing a screen check for a lab and the program did not pass my test. The student could not tell me what part of the code controlled the action that was in question. Due the amount of copying that goes on I have set the point value of the labs low and the point value of the tests high unless it is a project where each student produces a different "product".

I don't believe that cheating is only limited to plagiarism. I recently chaperoned a competition for a school sponsored club. The rules were clearly laid out prior to the event. The students told me they were following the rules. However, that was not the case. They defied both me and the rules and they paid the price. My question is why do students lie and cheat so easily?

My kids do everything in class so I do not have the problem, I can see what they are doing. One solution I have used in other situations is to give each student a unique assignment. Not unique enough to make it a royal pain to grade, but different enough that the codes cannot be identical. Students are rarely willing to help another student write from scratch.

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