It turns out that the American Association of Universities announced that it will be trying to answer this very question be conducting surveys this spring at 28 college and universities that represent over 800,000 students. The AAU's press release describes the study this way:
A team of experts from universities and Westat is developing the survey, based on an instrument developed by the White House Task Force to Protect Students from Sexual Assault. The survey will document the frequency and characteristics of campus sexual assault and sexual harassment, and assess campus climate in a way that allows for comparability of data across institutions and that protects the confidentiality of respondents.The press release doesn't provide details on the study's methodology, but according to the press release, “the survey is expected to be among the largest ever on sexual assault." Here's hoping for a successful and informative survey.