Ohio State officials said they can’t explain why more than 7 percent of students enrolled in the university’s emergency notification system didn’t get the message last Tuesday when a bomb scare shut down some of the Columbus campus. But experts said that even if 10 percent of the 32,000 subscribers in the Buckeye Alert system were left out of the loop, it would be considered a success.

“I don’t think you’ll ever have 100 percent communication, even if you have a skywriter go across the sky with a banner,” said Ara Bagdasarian, CEO of Omnilert, a leading emergency notification provider that works with more than 800 colleges and universities.

OSU has a contract with Twenty First Century Communications, a company that acts as the middleman between the university and cell phone carriers when OSU officials need to send updates about emergencies on campus.

Last Tuesday, when an anonymous bomb threat led authorities to shut down four campus buildings, OSU officials sent an alert to the company, which passed it along to cell phone carriers within nine minutes, said Bob Armstrong, director of Emergency Management and Fire Prevention at OSU.

However, the time it takes to reach individual cell phones depends on the how fast the carrier can deliver messages to customers, said John Rhind, director of marketing and communications for Columbus-based Twenty First Century Communications.

When it comes to campus security alerts, there are no official guidelines for colleges and universities. Most schools rely on continued discussions to update their systems, and many have decided that there is no one perfect way to reach students.

“One of our biggest missions is to educate schools on realizing the importance of a multi-modal approach,” said Bagdasarian, who launched e2campus.org, a website where school officials can share their emergency notifications policies. “Just a phone call, just an e-mail, just a text message is not enough. You need to notify students through as many means possible.”

OSU has a multi-pronged notification system, and officials decide on a case-by-case basis which methods to employ.

“These include, but are not limited to, text messaging, e-mail, voice mail, cable TV scroll, cable TV audio interruption, outdoor warning system and others,” Armstrong said.

Despite some complaints about the university’s alert system — which sends messages only to subscribers but will switch to a new system in 2011 that enrolls all students — officials at other universities said they have similar success rates reaching students with their systems.

“I feel 100 percent is almost impossible to reach, and on any planning scenario where you try to hit 100 percent, you fail, so you try to do what you can,” said David Cronk, director of emergency preparedness at University of Texas at Austin. “Reaching 95 percent is great, it’s fabulous.”

Armstrong said one of the most common reasons why students don’t get the Buckeye Alert notifications is because they changed their cell phone number without updating it in the alert system, or they have a phone plan that permits text messages only from people they know.

At Virginia Tech, officials have eight forms of communication they can use to alert students in emergencies, including electronic message boards in more than 450 classrooms and other major buildings.

“We believe that emergency notification requires many different channels,” said Lawrence Hincker, associate vice president for university relations at Virginia Tech.

Mark Owczarski, director of news and information at Virginia Tech, said text messaging — the most frequent way Buckeye Alerts are sent — can be inefficient during emergencies.

“With 45,000 people signed up, it can take up to 30 minutes if everything is working perfectly,” he said. “Thirty minutes is a long time in a true emergency.”

Owczarski said many buildings at Virginia Tech are made of stone, making it more difficult to receive phone messages.

“If you’re in a cell dead zone, you’re not going to get your text,” he said. “It has nothing to do with the vendor or product.”

Although many of Virginia Tech’s alert systems have been in place for almost a decade, a campus shooting in 2007 that left 32 dead and many others wounded spurred officials to rethink how they communicate with students.

“I would be dishonest if I said the tragedy didn’t have any effect. It clearly had an effect on a lot of people,” he said. “The world changed, higher education changed.”

Because of the shootings, the university developed a Web portal that synchronizes all the university’s different technologies with one signal. That’s also when administrators called for the electronic message boards and an emergency hotline, which OSU also has.

“As new technology presents itself, we’ve added them to the process as opposed to replacing any of the older stuff,” Owczarski said.

At the University of Texas at Austin, where a student opened fire in a campus library before killing himself in September, officials said they have no way to gauge whether all students received the text alerts that went out when the shooting began.

“We can definitely tell all 53,548 text messages went through without a problem,” Cronk said. “How do I know every student received it? I don’t. I don’t know how anybody can do that unless they have them all reporting in.”

Texas has 12 types of alerts, including a siren system and an emergency website. Cronk said multi-platform systems ensure redundancy, making it likely that most people on campus know about emergencies.

However, Cronk said students also need to take responsibility for themselves.

You “need to be your own first-responder,” he added.

With all the alert systems universities have in place, text messaging is the only one students have to sign up for at many schools.

Virginia Tech asks students to sign up for text alerts before they register for classes each semester. The school has about a 90 to 92 percent sign-up rate, Owczarski said.

When students enroll at the University of Texas, they are encouraged to give a phone number where they can receive text messages in case of an emergency.

The university also tests its emergency alert systems the first Wednesday of every month. Students receive an e-mail the day before, warning them about the test and reminding them to sign up for text alerts.

At OSU, officials are finalizing plans to switch the alert system to an opt-out program, where all students receive alerts through text message, e-mail or phone call unless they unsubscribe. Administrators said Friday that they were finishing those plans and said the switch has been in the works for years. The timing of the decision — three days after the bomb threat — is a coincidence, they said.

“We fully expect to reach this goal in 2011,” Armstrong said.