WASHINGTON — More than 20 percent of female undergraduates at an array of prominent universities said this year they were victims of sexual assault and misconduct, echoing findings elsewhere, according to one of the largest studies ever of college sexual violence.
The survey from the Association of American Universities (AAU) drew responses from 150,000 students at 27 schools, including most of the Ivy League. Researchers acknowledged the possibility of an overstated victimization rate, as there was evidence that hundreds of thousands of students who ignored the electronic questionnaire were less likely to have suffered an assault.
But the results add to growing indications that sexual assault is disturbingly commonplace at colleges and universities, especially among undergraduates living on their own for the first time. Though colleges already are on high alert to the problem — in part because of a White House task force formed last year to combat it — the survey findings underscore the seriousness and breadth of sexual assault's impact, and how difficult it will be to curb it.
The survey provides a wealth of insights about the prevalence of specific types of assault at a cross-section of public and private research universities; among them was the stark finding that 11 percent of female undergraduates said they experienced incidents of penetration that fit the criminal definitions for rape or sodomy, half of them saying it happened by force.
Others said they were victims of unwanted touching or kissing that could be defined as sexual battery.
"The leaders of our universities are deeply concerned about the impact of these issues on their students," Hunter Rawlings, the AAU's president, said. "Their participation in this and other climate surveys is an important part of their efforts to combat sexual assault."
The AAU's findings are roughly consistent with a Washington Post-Kaiser Family Foundation national poll, published in June, that found one in five young women who attended a residential college during a four-year span said they were sexually assaulted.
Other recent studies also have found high victimization rates at universities in Michigan, New York, Massachusetts and New Jersey. But some Justice Department crime data show that women in college are less likely to be victims of rape or sexual assault than those who are not students.
Education Secretary Arne Duncan told the Washington Post late last week that the number of students who experience sexual assault is "unacceptably high" — and has been for decades. Duncan had not yet been briefed on the AAU results, but he said the nation must confront the widespread prevalence of sexual assault in college.
"It is shockingly bad, but it is the truth," Duncan said. "It's just like gun violence. I'm shocked every day at the level of gun violence in this country. But it's the truth. We can either hide from that reality, or not."
Participants in the AAU survey included elite private universities such as Harvard and Yale, as well as public flagships such as the University of Florida and University of Texas at Austin.
The others were Dartmouth College (the only non-AAU member); the California Institute of Technology; Brown, Case Western Reserve, Columbia, Cornell, Iowa State, Michigan State, Ohio State, Purdue and Texas A&M universities; Washington University in St. Louis; and the universities of Arizona, Michigan, Minnesota-Twin Cities, Missouri-Columbia, North Carolina at Chapel Hill, Oregon, Pennsylvania, Pittsburgh, Southern California, Virginia and Wisconsin-Madison.
The only Ivy League school that did not take part was Princeton University.
The survey, conducted by the social science firm Westat, asked about individual experiences with sexual assault as well as perceptions on campus about the issue. Nearly all students at the 27 schools were canvassed in April and May, with confidentiality guaranteed. Nineteen percent responded, a lower rate than the survey team had hoped to attain.
The AAU's report did not provide detail on victimization rates at each school. Many participating universities plan to release their own data from the survey as early as Monday.
Among the key findings:
• Victimization rates varied widely from school to school. The share of undergraduate women who said they suffered sexual assault and misconduct ranged from 13 percent to 30 percent among the 27 schools. Overall it was 23 percent. Those at private universities were slightly more likely to be victims than those at public universities.
• Five percent of undergraduate men said they experienced sexual assault and misconduct, echoing a finding from the Post-Kaiser poll.
• Of students who said they were victims of physically forced penetration, about 25 percent said they told university authorities or law enforcement. Of those who said they were victims of physically forced sexual touching or kissing, 7 percent reported the incident. The dominant reason for why students who didn't tell authorities: They said it wasn't serious enough.
• Sixty-three percent of all students said they believe a report of sexual assault or sexual misconduct would be taken seriously by campus officials. Fifty-six percent said it was very likely or extremely likely that the safety of those reporting sexual assault and misconduct would be protected by university officials.
David Cantor, vice president of Westat, said the survey is one of the first of its kind to enable comparisons across institutions. He also said it is notable that the survey distinguishes between different types of attacks (penetration versus touching/kissing) and different situations (force versus incapacitation).
"Providing this level of detail is fairly unique among the campus climate surveys," he said. That was done "mostly by the request of the universities, to try to differentiate between incidents clearly quite different in nature."
The survey also is one of the first to gauge incidents in the context of the standard known as "affirmative consent," which calls for both people in a sexual encounter to communicate their active and ongoing agreement. California last year became the first state to enact a law requiring universities to include affirmative consent in student conduct policies. Many schools nationwide have moved in that direction.
The survey found that 11 percent of undergraduate women experienced penetration or oral sex without their "active, ongoing voluntary agreement." This rate ranged from 5 percent to 21 percent among the 27 schools.
"That will stimulate a lot of discussion," said Bonnie Fisher, a professor at the University of Cincinnati and a Westat consultant. "We as researchers don't know a lot about this — it hasn't been measured in the past."