The hysteria surrounding campus sexual assault reached a new pitch yesterday when MIT released the results of a survey on the subject. The university reported that 17 percent of female undergrads and 5 percent of male undergrads had been sexually assaulted, unleashing a flurry of articles and hand-wringing. “Activists against sexual assault have argued that such campus ‘climate’ surveys are crucial to exposing the extent of the problem, and such surveys were among the steps proposed this year by both a White House task force and a bipartisan group of senators,” the New York Times reported.

But is that what the survey actually showed? Only 35 percent of the student body opted to complete the survey, though all 11,000 graduate and undergraduate students were asked to. While there is no way to tell how the results may have differed had the entire student body completed the survey, it’s certainly reasonable to believe that the respondents were a self-selecting group, a big no-no in scientific research. The organizers certainly seemed to expect a certain kind of respondent, based on the gifts it offered as compensation for the 10-15 minutes they estimated the survey required: “Your choice of $10 TechCASH, a $10 donation to Violence Prevention and Response at MIT Medical, or a $10 donation to Stop Our Silence, a student group dedicated to bringing awareness to the problem of sexual assault.” While it’s possible that these 3,844 students are a perfect sample set for MIT’s 10,831 students, it’s also possible—even likely—that those who have been assaulted are more likely to respond to a survey about that topic. Self-selection is usually suspect in scientific studies, because people with opinions tend to care more.

The survey itself struggles throughout to contain what might be called its tonal bias. It starts off with a statement some might call unscientific:

TRIGGER WARNING: Some of the questions in this survey use explicit language, including anatomical names of body parts and specific behaviors to ask about sexual situations. This survey also asks about sexual assault and other forms of sexual violence which may be upsetting. Resources for support will be available on every page of the survey, should you need them.

While the organizers of the survey might be commended for their intense desire to help students with the emotions the survey may evoke, the trigger amounts to a leading question. It’s very easy to imagine that the results of the survey might be in some way affected by being told its questions are very likely to upset you.

The survey then asks, among other questions, whether students have been sexually harassed, sexually assaulted, or raped. Ten percent of female MIT undergrads say they have “been sexually assaulted.” But MIT then goes on to say it has found that 17 percent of female undergraduates have been sexually assaulted. When offering this larger number, MIT defines sexual assault as “unwanted sexual behaviors… involving use of force, physical threat, or incapacitation.” This leaves a glaring, unanswered question: If 17 percent of female undergrads have been subjected to unwanted sexual behaviors “involving use of force, physical threat, or incapacitation,” why do only 10 percent of them report having been sexually assaulted (11 percent if you count those who have been assaulted and raped)? Another 12 percent of female undergrads who reported unwanted sexual behaviors did not claim that they had been sexually assaulted or raped. The university is clearly using a broader definition of sexual assault than its own students.