The original IPDE acronym was first taught back in the 1950s traffic education. I believe the author that came up with it was Dr. White (I'd have to go back and check). Jeff Cooper used a version of it when he did his whole "code" thing. Code white, code red, etc.. when attempting to keep from being code white when you should be more aware. As Slapout mentioned a version of SIPDE is used for EVOC, and I have even ran across a version of it used for scout training in the Marine Corps.