Lyra Bartell, right, of Richmond, Va., hugs her friend, Irene Burgoa in front of the undergraduate admissions building at the University of Virginia. The door of the building has notes relating to sexual assault allegations. (Steve Helber/AP)

More than 20 percent of female undergraduates at an array of prominent universities said this year that 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 drew responses from 150,000 students at 27 schools, including most of the Ivy League. Armed with extensive data on the scope of the problem at their own campuses, leaders of big-name universities said they are mobilizing to confront sexual assault as never before.

Yale University President Peter Salovey said he found “extremely disturbing” results indicating more than one-quarter of undergraduate women at the elite school in New Haven, Conn., were victims of sexual assault and misconduct.

“The prevalence of such behavior runs counter to our most fundamental values,” Salovey said. “It threatens individual students, our learning environment and our sense of community.” Other university leaders, speaking virtually in unison, said the results sounded an alarm that must be answered.

Researchers acknowledged the possibility of an overstated victimization rate because there was evidence that hundreds of thousands of students who ignored the electronic questionnaire were less likely to have suffered an assault.

Sexual assault at major universities

But the results add to growing indications that sexual assault is disturbingly commonplace on college campuses, especially among undergraduates living on their own for the first time. Although colleges already are on high alert about 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 effects and how difficult it will be to curb them.

The AAU 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 had experienced incidents of penetration or attempted penetration, half of them saying it happened by force. These incidents would fit the definition of rape or sodomy.

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 R. Rawlings III, 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 that 1 in 5 young women who attended a residential college during a four-year span said they were sexually assaulted.

Other recent studies also have found similarly high victimization rates. 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 Post last week that the number of students who experience sexual assault is “unacceptably high” and that it has been for decades. Duncan said the nation must confront the widespread prevalence of sexual assault in college.

“It is shockingly bad, but it is the truth,” Duncan said. “We can either hide from that reality or not.”

KC Johnson, a Brooklyn College history professor who tracks college sexual assault and due-process issues, said he is skeptical of the findings.

“If you take this data literally, it would suggest a violent crime rate at most campuses higher than in any city in the country,” he said. “Which I think is somewhat dubious.”

Johnson said he was puzzled by survey results that showed many victims of forced, non-consensual penetration didn’t consider the incident serious enough to report to authorities. “We’re talking about college students at elite institutions,” he said. “They understand what sexual assault is.”

Participants in the AAU survey included a range of public and private schools, and the share of undergraduate women who said they had been sexually assaulted during their time on campus varied: It was 19 percent at the University of Texas at Austin, 24 percent at the University of Virginia, 26 percent at Harvard University, 28 percent at Yale and 30 percent at the University of Michigan.

“These deeply disturbing survey results must spur us to an even more intent focus on the problem of sexual assault,” Harvard President Drew Gilpin Faust said in a letter to the university community. “That means not just how we talk to one another about it, not just what we say in official pronouncements, but how we actually treat one another and live our lives together.”

“One sexual assault is too many,” said University of Texas at Austin President Gregory L. Fenves. “It is essential that we foster a campus that does not tolerate sexual assaults while strongly encouraging victims to come forward and report incidents.”

Other participants 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, Florida, Minnesota-Twin Cities, Missouri at Columbia, North Carolina at Chapel Hill, Oregon, Pennsylvania, Pittsburgh, Southern California and Wisconsin at Madison.

The only Ivy League school that did not participate 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.

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, or attempted 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. “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.”

●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 and 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.

Peyton M. Craighill contributed to this report.