Tovia Smith filed a report with NPR that detailed the psychometric delicacies of trying to measure the sexual assault rates on a college campus. I think this story is highly relevant to college students. I also think it also provides an example of the challenge of operationalizing variables as well as self-selection bias.
This story describes sexual assault data collected at two different universities, Rutgers and U. Kentucky. The universities used different surveys, had very different participation rates, and had very different findings (20% of Rutgers students met the criteria for sexual assault, while only 5% of Kentucky students did).
Why the big differences?
1) At Rutgers, students where paid for their participation and 30% of all students completed the survey. At U. Kentucky, student participation was mandatory and no compensation was given. Sampling techniques were very different, which opens the floor to student discussion about what this might mean for the results. Who might be drawn to complete a sexual assault survey? Who is enticed by completing a survey for compensation? How might mandatory survey completion effect college students' attitudes towards a survey and their likelihood to take the survey seriously? Is it ethical to make a survey about something as private as sexual assault mandatory? Is it ethical to make any survey mandatory?
2) Rutgers used a broader definition of sexual assault. For instance, one criteria for sexual assault was having a romantic partner threaten to break up with you if you didn't have sex with them. Jerk move? Absolutely. But does should this boorish behavior be lumped into the same category as rape? Again, this bring up room for class discussion about how such definitions may have influenced the research findings. How can we objectively, sensitively define sexual assault?
Here is an additional news story on the survey out of University of Kentucky. Here is more information about Rutgers' survey (you can take a look at the actual survey on p. 44 of this document).