PHILADELPHIA (CBS) - A new study by the American Association of University Women found that 48% of students, 7-12th grade, experienced verbal, physical or online sexual harassment at school during the last school year.

Episodes were mostly unseen by adults — everything from gossip, teasing, groping to severe physical attacks to enforce gender stereotypes, bully and retaliate. Nearly a third became harassers themselves who thought it was “no big deal.”

New York City middle schools are using “Shifting Boundaries,” a program in which schools post information on sexual harassment and students within classes and campus-wide talk about the school’s sexual environment, legal and school rules related to harassment.

“Hot spots” are identified where students feel most unsafe and school administrators have been able to change travel patterns and hall monitor locations.

Research showed that schools implementing the program reported 26-47% fewer incidents of sexual violence and 50% less physical and dating violence since the program’s start.

Read more about teen harassment in Education Week.

Reported By Dr. Marciene Mattleman, KYW Newsradio