HOUSTON- Something about Monday's campus alert at Ohio State University got a lot of people's attention--the part that instructs people to either: "Run, Hide or Fight" back.

It's part of an "active shooter" response movement that started in Houston.

The Office of Emergency Management helped develop the three-word mantra back in 2012 after the movie theater shootings in Aurora, Colorado.

OEM says it was originally developed for Houston and its five surrounding counties but now they are three words law enforcement and other emergency officials around the country feel are vitally important.

The five minute video is displayed prominently on the city of Houston's website, explaining what to do in an "active shooter" scenario.

OEM says after doing research, they came up with the easy to remember slogan of "Run, Hide, Fight"--one that they say works in a variety of settings.

"It works because it's a sequence of orders," said Michael Walter, public information officer for the Office of Emergency Management. "Number one and the safest thing we'd want you to do is run. If you can run that's the safest thing you can do. If you are unable to run, then hide. If you are unable to hide, you're going to have to use the last possible resort which is to fight back."

During Monday's incident, Ohio State University's Department of Public Safety tweeted the phrase out.

"The school did training ahead of time with their students on this protocol so when they said "run, hide, fight" in their emergency alert that hearkens back to training they had already received," Walter said.

OEM says a number of different organizations use this slogan, including the Department of Homeland Security.

Constable Alan Rosen of Harris County Precinct One told us he believes many people freeze in these types of situations so it's important to train people to react instantaneously.