Cheating on Homework...Just stop grading it!

I just read this amazing study done with MIT Calculus-Based Physics classes.
http://link.aps.org/doi/10.1103/PhysRevSTPER.6.010104

The basics are that students using the Pearson online system, MasteringPhysics, were assigned problems. The system measures how long it takes for a student to answer the problem, and they decided students who answered in less time than it takes to read the problem were copying from someone else. They coupled this with some qualitative information from surveys.

The results are not too surprising. Students who copied got lower scores on the test questions that were similar to the homework problems. Students also copied more as the deadline for the assignment got closer. Interestingly, the amount of copying did not have a significant effect on the Mechanics Baseline Test learning differences.

I have been a stamp the work teacher for years. Students get a stamp for getting ALL of the problems done on the page. They may be wrong, but they must be done. This is to ensure that they are prepared to discuss the assignment, or at least follow the discussion. What about the kid who did as much of the assignment on his/her own, but didn't have time for the last few. Tough patooty. No Stamp For You!

What about the kid who copied it in the morning or five minutes before class from a buddy? They are rewarded with the full points. I justified it by saying they would lose points on the tests. I think I secretly wanted them to lose points on the tests as penance for their cheating. Jesus, what am I doing?

Homework is not graded anymore.