WEST LAFAYETTE, Ind. – The conventional advice for surviving a mass shooting is flawed, according to a Purdue study.

Police and the federal Department of Homeland Security preach “run, hide, fight” — run if you can, hide if you can’t, fight the gunman as a last resort. Purdue’s Homeland Security Institute tested that advice with a computer simulation of the Columbine massacre. Director Eric Dietz says those tests confirm running is the best option — he says especially if you already have a head start, it takes only a few seconds to get out of a gunman’s range. But the simulation finds the customary Plan B of hiding just makes you a sitting duck. Dietz says hiding only works as a steppingstone until you can run.

And if you’re too close to the gunman to run out of range, Dietz says trying to tackle or distract him may be the most realistic option.

The Columbine killers murdered 12 classmates and a teacher in 1999. Security video supplies second-by-second data on their movements from the start of the shooting until it ended with their suicides. Purdue plugged that information into logistics software, then tinkered with what the others in the school were doing to see what might have changed.

Dietz, who served as Indiana’s first homeland security director from 2005 to 2008, says states and schools have invested heavily in safety measures. He says the goal of the institute’s research is to make sure those decisions are supported by evidence of what’s most effective.

Dietz plans further research on how much distance from a gunman tips the balance toward being able to run. The Columbine simulation found running was the clear choice at more than 20 feet away, while if you’re within arm’s length, the best option may be to fight.