This paper examines the behavior of students in a physics class at MIT, especially how much homework copying was down, and the impact on the exam results. It is very fascinating.
Abstract:Submissions to an online homework tutor were analyzed to determine whether they were copied. The fraction of copied submissions increased rapidly over the semester, as each weekly deadline approached and for problems later in each assignment. The majority of students, who copied less than 10% of their problems, worked steadily over the three days prior to the deadline, whereas repetitive copiers (those who copied >30% of their submitted problems) exerted little effort early. Importantly, copying homework problems that require an analytic answer correlates with a 2(σ) decline over the semester in relative score for similar problems on exams but does not significantly correlate with the amount of conceptual learning as measured by pretesting and post-testing. An anonymous survey containing questions used in many previous studies of self-reported academic dishonesty showed ∼1/3 less copying than actually was detected. The observed patterns of copying, free response questions on the survey, and interview data suggest that time pressure on students who do not start their homework in a timely fashion is the proximate cause of copying. Several measures of initial ability in math or physics correlated with copying weakly or not at all. Changes in course format and instructional practices that previous self-reported academic dishonesty surveys and/or the observed copying patterns suggested would reduce copying have been accompanied by more than a factor of 4 reduction of copying from ∼11% of all electronic problems to less than 3%. As expected (since repetitive copiers have approximately three times the chance of failing), this was accompanied by a reduction in the overall course failure rate. Survey results indicate that students copy almost twice as much written homework as online homework and show that students nationally admit to more academic dishonesty than MIT students.
The impact on the exam results is very interesting. Students who copied more than 30% of their homework shows poorer performance in the exams. This is not surprising for many of us who have taught such subjects. I'm sure many of us have had suspicions on why a question that is similar to the one that the students have done correctly in a homework assignment, still can't be answered correctly.
But what made me laughed out loud was this passage in the paper:
Briefly, we found that students commit about 50% more copying than they self-reported on the self-reported survey. We showed that actual copying from both 2003 and 2005 data correlated with demographic factors: being male and being a business major as found in previous self-reported dishonesty surveys. Since our freshmen had not declared a major when they took the survey, we showed that copying is a leading indicator of becoming a business major.
This is hysterical, if somewhat sad. I wonder if this is a root cause of our economic debacle? :)
 D.J. Palazzo et al., Phys. Rev. ST Phys. Educ. Res. v.6, p.010104 (2010).