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One in five women in college sexually assaulted: an update on this statistic

The Phi Kappa Psi fraternity house at the University of Virginia in Charlottesville, Va., which was the subject of a discredited Rolling Stone article alleging a gang rape at the house  (AP Photo/Steve Helber)

“We know the numbers: one in five of every one of those young women who is dropped off for that first day of school, before they finish school, will be assaulted, will be assaulted in her college years.”

–Vice President Biden, remarks on the release of a White House report on sexual assault, April 29, 2014

“It is estimated that 1 in 5 women on college campuses has been sexually assaulted during their time there — 1 in 5.” 

–President Obama, remarks at White House, Jan. 22, 2014

This is an update of an article that originally appeared on May 1, 2014. It originally had a Pinocchio rating but that has now been removed in the wake of the publication of The Washington Post-Kaiser Foundation nationwide survey that confirmed the 1 in 5 statistic. The original issue with the statistic was that it was based just on a sample of two universities but was being treated as a nationwide sample. But that concern no longer exists now that a nationwide poll of college-age women has achieved the same result.

Reports of sexual assault on college campuses spurred the White House early in 2014 to launch a task force to examine the issue. The group’s report was issued on April 29, and the first sentence of the report echoes what both the president and vice president have asserted in public: “One in five women is sexually assaulted in college.”

Where does this oft-repeated statistic come from? We dug into the data so you don’t have to.

The Facts

This statistic is derived from a 2007 study, The Campus Sexual Assault Study, which was conducted for the Justice Department’s National Institute of Justice. The researchers, led by Christopher Krebs of RTI International, also surveyed men, but the statistic cited by the administration focuses on women so we will look carefully at that part of the study.

In the winter of 2006, researchers used a Web-based survey to interview undergraduates at two large public universities, one in the Midwest and one in the South. A total of 5,446 undergraduate women, between the ages of 18-25, participated as part of a random sample. The survey was anonymous and took about 15 minutes to complete. (Participants received a $10 certificate for participating.)

So, first of all, it’s important to remember that this is a single survey, based on the experiences of students at two universities. As the researchers acknowledged, these results clearly can be generalized to those two large four-year universities, but not necessarily elsewhere. Moreover, the response rate was relatively low:

“Another limitation of the CSA study, inherent with Web-based survey, is that the response rates were relatively low. Although the response rates were not lower than what most Web-based surveys achieve, they are lower than what we typically achieve using a different mode of data collection (e.g. face-to-face interviewing).”

The survey found that 1,073 women, or 19 percent, said that they experienced attempted or completed sexual assault since entering college. The actual breakdown was that 12.6 percent experienced attempted sexual assault and 13.7 percent experienced actual sexual assault. (There was some overlap.)

The sexual assault instances were further divided into sexual assault while incapacitated from drugs or alcohol or sexual assault through physical force. Most of the sexual assaults were identified as rapes, though the report said “sexual battery” could have included “sexual touching,” such as forced kissing or fondling.

Notice that the percentage of sexual assaults –13.7 percent—was lower than the one-in-five figure cited by administration officials. (It is more like one in seven.) That’s because the president and vice president used careful phrasing that covered a student’s entire time in college. The overall survey interviewed students that included freshmen, sophomores and juniors.

In a 2009 report, the researchers released a closer look at the data (embedded below). This report showed that out of the subset of seniors surveyed (1,402 women), that 19 percent (about 287) had experienced sexual assault.

College Women’s Experiences with Physically Forced, Alcohol- or Other Drug-Enabled, and Drug-Facilitated Sexual Assault Before and Since Entering College by GlennKesslerWP

“Women surveyed in their senior year of college (those having the longest risk period for sexual assault since entering college) had the greatest cumulative prevalence of each type of completed sexual assault,” the report said, referring to Table 1. “Almost 20% of the seniors experienced some type of sexual assault since entering college, with 6.9% experiencing physically forced sexual assault and 16.0% experiencing incapacitated sexual assault.”

In other words, information that is localized to the seniors at two colleges has now been extrapolated by politicians to the universe of college experience. (The report itself states that the data are limited just to those universities.) And to some extent, the results depend on how questions are phrased and answers interpreted. Below we have embedded the key questions that led to the statistic cited by the White House.

Key Questions in the Campus Sexual Assault Study by GlennKesslerWP

On its Web site, the National Institute of Justice notes that rapes and other forms of sexual assault are among the most underreported crimes, but that “researchers have been unable to determine the precise incidence of sexual assault on American campuses because the incidence found depends on how the questions are worded and the context of the survey.” It said that two parallel surveys of American college women were conducted in 1997 and came up with very different results, with one survey showing rapes were 11 times higher than the percentage in the other survey. The reason appears to be because of how the questions were worded. (Hat tip to Washington Post polling analyst Scott Clement for pointing us to this page.)

NIJ adds:

“Regardless of which studies are most accurate, the often-quoted statistic that one in four American college women will be raped during her college years is not supported by the scientific evidence. Nonetheless, several studies indicate that a substantial proportion of female students — between 18 and 20 percent — experience rape or some other form of sexual assault during their college years.”

Krebs made the following points in an e-mail in May, 2014:

We approached this project objectively and implemented it with as much methodological rigor as possible.  This gives us confidence in the results.  I do think there is room for improvement in our methods and I think a larger sample of universities and respondents would yield results that are more representative, but in the face of some significant challenges we implemented a study using solid methods and we have tried to be very clear about what we did, how we did it, and what we learned.

Moreover, Krebs, in an article for Time magazine published in December, 2014, wrote: “There are caveats that make it inappropriate to use the 1-in-5 number in the way it’s being used today, as a baseline or the only statistic when discussing our country’s problem with rape and sexual assault on campus.”

In December, 2014, the Bureau of Justice Statistics released a study titled “Rape and Sexual Assault Victimization Among College-Age Females, 1995–2013,” which suggested much lower levels of sexual assault than indicated in the Campus Assault Study. But questions have been raised whether the survey used for the report, the  National Crime Victimization Survey, offers an adequate measure of the incidence of rape; a National Research Council report released in 2014 offered recommendations on how to improve it.

Still, the report did indicate interesting trends over time, including the fact that sexual assault on campus had been declining in recent years–and that the incidence of sexual assault was higher for women who were not in college. The report also offered a useful guide to the differences between various studies of sexual assault on campus, including this caveat about using the Campus Sexual Assault Study:  “Because of the limited population included in the CSA, it should not be assumed that findings from the survey are representative of the population of persons ages 18 to 24 or even to college students specifically.”

Given that an arm of the Justice Department now has provided this warning about the one in five statistic, The Fact Checker asked the White House to explain why the president and the vice president expressed the data in such sweeping terms. Recall that Biden had said, “We know the numbers: one in five of every one of those young women who is dropped off for that first day of school, before they finish school, will be assaulted, will be assaulted in her college years.”

A White House spokesperson, who asked not to be quoted, said that the one in five statistic was consistent with other studies, pointing in particular to two surveys: a 2000 Justice Department study that reported that, over a seven-month period, 2.8 percent of college women faced rape victimization (completed or attempted) and a 2014 MIT survey which found that 17 percent of female undergraduates experienced one or more unwanted sexual behaviors.

But there are issues with both surveys. The 2000 report could be interpreted as suggesting that one in five women might face rape victimization over four or five years in college, but the authors conceded in 2010 that “admittedly, these projections are speculative and await longitudinal studies that follow women throughout their college careers.”

Meanwhile, the MIT sample was based on self-selected responses, so its data could not be used as any sort of confirmation. The university itself warned that the numbers were not representative of all women at MIT: “Because the survey was not a random sample and was voluntary…it would be a mistake to use these numbers to generalize about the prevalence of unwanted sexual behavior in the lives of all MIT students.”

The Pinocchio Test

In the original May column, The Fact Checker left this a “verdict pending,” awaiting additional information. As an interesting article from the University of Minnesota-Duluth newspaper makes clear, sexual violence is too rarely reported. So the White House should be applauded for calling attention to this issue; as part of its effort the White House task force is urging colleges to undertake climate surveys and pushing for more research on the prevalence of sexual assault.

But the BJS warning about the use of CSA data demonstrates the president and the vice president went too far in suggesting the “one in five” statistic applied to all college students. Instead, this oft-cited statistic comes from a Web-based survey of two large universities, making it misleading to suggest that it is representative of the experience of all college women.

Given the uncertainty of the research — and various surveys and anecdotal accounts indicating there likely is a serious problem of sexual assault on campuses across the country — we are going to start out with a single Pinocchio. We will monitor how the president, the vice president and other administration officials use this statistic in the future, and will update this column further as new research emerges.

UPDATE, June 12, 2015: Please read the extensive Washington Post report on a nationwide poll that confirmed the 1 in 5 statistic

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