“Back Off, Bully!”

The next time a school-bus bully harasses a student on the way home, the victim has a new way to fight back — a cell phone.

That’s thanks to a group of enterprising high school students who came up with an award-winning app named BOB.

BOB, which stands for ​“Back Off Bully,” is the brainchild of the 15 students in Adam Scott’s research, design and development class at Metropolitan Business Academy, a magnet high school on Water Street.

With the touch of a finger on a cell phone, kids can now anonymously report a bullying incident to school administration. Go to BackOffBullyApp.com to check out the web application, which works on any cell phone, tablet or computer with access to the internet.

The app propelled Scott’s class to acclaim at a recent statewide competition in Hartford hosted by the Center for 21st Century Skills.

Christine Puglisi, a sophomore and the lead developer on the app, led a visitor on a tour through the program during a visit to the class Thursday.

As part of the competition, students formed a business called Spontaneous Tech. After ruling out other runner-up ideas — such as an app to help kids find legal skateboarding spots and connect with community-service options — the class settled on creating an anti-bullying tool.

An app made perfect sense, Christine said, because it meets students in their comfort zone. Kids might be ashamed or embarrassed to go down to the main office in person to issue a bullying report, she argued, but they might be more willing to fill out an anonymous form on a cell phone.

“So often, kids hide behind phones to cyber-bully and do negative things,” she added. ​“We want them to use phones for a positive use — to start changing the world.”

The first obstacle they came across was the danger of false reports. School administrators considered that problem, and replied that they thought the tool would be useful even if only 2 of every 10 reports turned out to be true, Christine said.

Students set about putting together the app. Some worked on graphic design. Some focused on web design. Others created social media sites, as well as T‑shirts and buttons. Christine took the lead on the programming end.

She said while most schools were doing a ​“demonstration app” based on ready-made chunks of code, she found that format too limiting and decided to learn to program HTML herself.

The final product offers the student three options: Report bullying, where kids have to agree to a ​“terms of use” to give true accounts; get help, where students can call a counselor to make an appointment; and an informational section called ​“What is Bullying?”

The data is collected and sent to the school administration. Christine said she hopes the school will help administrators notice patterns in bullying: For example, if a kid always gets harassed in the stairwell during second period, the school can staff that spot and prevent the behavior.

Metropolitan students launched the program in their own school a month ago. They’ve been busy promoting the tool around school, including giving talks to freshmen about how to use it. They plan to make a big push with next year’s freshmen to use the tool, introducing it at freshman orientation.

Already, other schools are showing interest in the app, Christine said. It turned out to be ​“a lot bigger than we thought it would be.”

The hard work paid off on May 19, when the students won big at a competition at the CT Student Innovation Expo at the XL Center in Hartford. Students competed against five teams from across the state. They won three awards in their category: ​“outstanding mobile app design,” ​“outstanding marketing and social media,” and ​“outstanding project.”

They also beat 26 other schools in a statewide competition for ​“outstanding interpretation” of the conference theme that year, which was ​“adaptability.” The competition was among schools that are participating in math, science and technology classes through a not-for-profit called EDUCATION CONNECT. The organization is offering in-depth classes at three New Haven high schools, as well as others across the state, as a result of a $4.5 million competitive Investing in Innovation grant.

Teacher Scott beamed Thursday as his students showed off four plaques in their spiffy computer room. He said the project took a lot of collaboration, as well as input from administrators, counselors and the Foundation for the Arts and Trauma, which does some work at the school.

“They took the framework and ran with it,” he said.

Students will be showing off their app at a June 9 open house at the school from 10 a.m. to 1 p.m. The event is free and open to the public.