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Justice Lab

The Dueling Data on Campus Rape

A new federal victim survey challenges the ‘one-in-five’ notion.

On Monday Emily Yoffe published a long piece in Slate arguing that the Obama administration and college officials have become overwrought in their concern about campus sexual assaults. Yoffe heaped particular scorn on one of the common talking points in the campus rape debate: the claim that one-fifth of all female students have been victimized.

A federal report released today seems, at first glance, to back Yoffe. It estimates that fewer than one percent of women aged 18 to 24, and even fewer female college students — .6 percent — have been raped or sexually assaulted. What accounts for the phenomenal gap? And is the “one-in-five” claim as wildly off the mark as Yoffe implies?

Maybe not. The two studies are based on surveys that asked different questions of different populations under different circumstances. And while Yoffe accurately pointed out the limitations of the “one-in-five” study, the .6 percent estimate has its own set of serious shortcomings. In short: don’t take either number as gospel.

Below, some of the research issues that account for the divergent stats.

Who is a student?

The report released today by the Department of Justice is based on the National Crime Victimization Survey (NCVS), which relies on interviews with 160,000 Americans over the age of 12. The survey asks respondents if they are attending college, and classifies everyone who says “yes” as a college student, even if they are enrolled solely in online courses or spend only a few hours per week on an actual campus.

The one-in-five estimate, on the other hand, comes from the federally funded Campus Sexual Assault Study (CSA), a 2006 web survey of more than 5,000 women and 1,000 men attending two unnamed, large public universities. As Yoffe points out, two campuses is an awfully small sample. Christopher Krebs, a senior researcher at a non-profit research group, RTI International, who led the Campus Sexual Assault Study, acknowledges that. “The one-in-five statistic is not anything we trotted out as a national statistic,” he says. “But it has certainly been used in that way” — most prominently by President Obama.

Still, there are advantages to the CSA approach. Although its sample is small, it is tightly focused on full-time students at traditional brick-and-mortar universities. Full-time students who live on campus are the students at the center of the national conversation about college sexual assault. Previous research shows that female students who live in dorms or sorority houses are more likely to be sexually assaulted than female students who live with parents or in off-campus residences. The CSA may have come up with a higher estimate of victimization, in part, because its student respondents at traditional colleges were more vulnerable.

How is sexual assault described?

Yoffe critiques the CSA for asking respondents about low-level sexual assaults, including “rubbing up against you in a sexual way, even if it is over your clothes.”

The NCVS also inquires about a broad range of sex crimes, ranging from rape to unwanted touching. Where the two surveys differ is in how specific and graphic their questions are. The NCVS simply asks if respondents have been the victims of “rape” or have been forced to engage in “unwanted sexual activity” such as “grabbing, fondling, etc.”

The CSA is much more detailed. It inquires about sexual penetration with body parts or objects in specific orifices. It also prompts women to reflect on whether they have ever had sex while they were unable to consent due to being “passed out, drugged, drunk, incapacitated, or asleep.” By excluding questions about the victim’s substance use, the NCVS may have missed some crimes. Separate research suggests 44 percent of American college students binge drink, and that binge drinking is associated with unwanted sexual contact.

The Justice Department is currently considering whether to ask more explicit questions on the NCVS. More detailed questions tend to yield more crime reports. “A lot of people, if you’re on a date and a guy attacks you, they don’t view that as a rape,” says Callie Rennison, a criminologist at the University of Colorado - Denver, who previously worked on the NCVS while employed by the Department of Justice. “People may not reveal it” unless they are asked about that exact type of incident.

Another limitation of the NCVS is that respondents are told they are taking a survey about crime. “We know from talking to victims of sexual violence, especially those who are in college, that many don’t define what happened to them as a crime,” Krebs says. “If that’s the case, they may be unlikely to report it as a crime in the NCVS.”

Where does the survey take place?

Last year the National Research Council published a report suggesting that young adults may be reluctant to honestly answer questions about sexual assault posed to them during the NCVS. The required in-person interviews typically take place in homes, where parents or other family members might be present. And even during the follow-up phone interviews, someone else might be listening. The web-based nature of the CSA thus offered more privacy, which could have led to more reports of sexual assault.

When were subjects victimized?

The NCVS asks respondents about incidents over the past six months, while the CSA asks about incidents during the entirety of one’s college career. The longer time frame of the CSA produces more incident reports, especially among older students.

So what’s the best estimate?

Yoffe considered the various surveys and universities’ own (often misleading) reports of sex crimes, ultimately guessing that .27 percent of female students have been sexually assaulted. But the truth is that there is no ideal measure of college student sexual victimization, one that has a large sample, offers privacy, tracks individuals over multiple years, and considers factors such as where a student lives or whether she has had very specific types of unwanted sexual contact.

“On any topic, there’s no perfect survey and no perfect measurement, and that’s why we should do multiple attempts,” Rennison says.

There is new research on the horizon. Krebs is currently working with the Justice Department on an updated sexual assault survey, which he plans to administer to students on 10 to 15 campuses this spring. “Now we’re trying to do this in a bigger way, and a better way, than what we did before,” he says. “We’re trying to take advantage of new technologies and trying to develop a methodology and survey instrument that we think will be state of the art and will collect the most valid and reliable data.”

Krebs expects the results to be available in late 2015. Don’t expect the argument to end then.