Wednesday, April 27, 2011
PCRM - Cheating
Experience during the past few years with multiple-choice tests scored by only counting right marks has made it clear that cheating occurs at all levels from student to state house. The usual method for detecting this activity is to compare observations with probabilistic models. The down side of this approach is that the models are generally too simplistic to match the real world. Also, school administrators value “catching them in the act” (a very difficulty thing to do) far more than “statistics” applied to individual students.
An alternative is to make use of the information content in each student answer string. Answer strings can be matched by collating, filtering and sorting. Presumptive cheating is then a marked departure from the class norm. Confirmed cheating usually requires additional information that is accepted by students and administrators.
The PUP copy detector shows a suspect pair on Part 1&2 involving student 11 and 29 with a standardized index (Z) value of 3, a marginal level of detection. This individual pairing shows a string of 14 identical marks followed by strings of 2 and 7 identical marks. This is presumptive cheating.
The student counseling matrixes show identical strings within unfinished (-A@D@EE-) and within misconception and guessing (D@EE-A). No other of the fifty students marked in this fashion. Question 9 was flagged by Ministep as most unexpected right. Only two students with the lowest scores shared this classification.
I would not call this a confirmed case of copying, as six of the seven identical pairs were non-critical, that is the identical wrong marks were too common on the test. In my judgment, this pair did not fail the test for independent marking. Failure would require additional information. There is also no noticeable marked departure from the class norm.
A record of presumptive cheating is easy to keep on mark matrixes sorted by student ID and question number, PUP 3b, or by score and difficulty, PUP 3c. Answer sheets were coded with three spaces each, for test number and seat number. Students filled in their three-digit student number. This information generally permitted confirming cheating, without resorting to multiple test forms (a negative, time wasting, procedure). Relying on their written record (answer sheets), just as scientists do, modeled the ethics of science as these students explored and developed their ability and desire to make sense of biological literature for the rest of their lives. (On the Internet, it is even more important to have formed the habit of questioning and confirming the information encountered.)
The most successful classroom policy I used to manage copying was to clearly state that answer sheets would be checked for cheating to protect honest students. Any answer sheet that failed the check would receive a score of zero. I would help any student who wanted to protest this decision to student affairs (no student every protested, which was, in itself, a further confirmation of cheating). Two students were detected twice over a nine-year period. They readily admitted copying but were both unhappy with themselves over finding their “fool proof” methods in other courses did not work here.