Hard data on students using W's to enhance their GPAs? I teach at a community college in California, where students can drop a course with a grade of "W" up until the 12th week of the semester. Within the last year or so, I seem to be seeing an increase in the number of students who find themselves passing the course at the 12th week, but who decide to drop because they want a better grade and are willing to take the course again later. However, I'm not sure that this increase is real, since my sample size is small. And if it is real, I don't know how widespread the phenomenon is or how to probe for possible causes for the change, since a number of different variables have changed in this time frame (including changes in state law and school policy).

Is there any source of hard data or method for getting data on this? I think there's a pretty big literature on student success and persistence, but the impression I get is that a lot of the literature takes it as a matter of definition that if the student doesn't pass the course with a C, it's because the student didn't "succeed," i.e., the student's academic performance wasn't passing. It seems like it would be difficult to gather statistically robust data to measure the phenomenon of drops due to grade dissatisfaction, since instructors aren't systematically asked to submit or retain the grade records of students who are no longer enrolled at the end of the term.
I've just done 15 minutes of moderately focused research, and found nothing.
It looks like in most exit surveys students claim to have dropped because of family or work conflicts, which may be true but is not the acute reason for the drop for your students.

A Google search for "drop and retake" finds dozens of recommendations like this for pre-med and other highly grade-motivated students. 

I'm rather intrigued, actually. If these students could be motivated to stay and get the grade, it would save the state a lot of money. And if they couldn't drop after Week 2, they might work much harder much earlier. 

I sense a possible research project...