IEORs "don't make semiconductors, computers, bridges, but we are making SYSTEMS work"
"IEOR is in brief the application of engineering methodology to non-traditonal engineering problems...we use the tools of enginering to solve problems in other areas such as: finanicial areas, communications, government, and industry" ("Homeland security, health care...")
"OR is really the field that deals w/ the applied science side of decision making; its taking mathematical models to model a real sytem where usually you have to allocate a scarce set of resources to improve the effiencey of the system. It could be a transportation sytem....manufacturing sytem...finance..."
http://cap.cs.columbia.edu/john/IEOR...deoplayer.html