awareness during learning, and later extended to mental workload and fatigue. Situation awareness appears in the technical literature as early as 1983, when describing the benefits of a prototype touch-screen navigation display. During the early 1980s, integrated “vertical-situation” and “horizontal-situation” displays were being developed for commercial aircraft to replace multiple electro-mechanical instruments. Integrated situation displays combined the information from several instruments enabling more efficient access to critical flight parameters, thereby improving situational awareness and reducing pilot workload. The term was first defined formally by Endsley in 1988. Before being widely adopted by human factors scientists in the 1990s, the term is said to have been used by United States Air Force (USAF) fighter aircrew returning from war in Korea and Vietnam. They identified having good SA as the decisive factor in air combat engagements—the "ace factor". Survival in a dogfight was typically a matter of observing the opponent's current move and anticipating his next move a fraction of a second before he could observe and anticipate it himself. USAF pilots also came to equate SA with the "observe" and "orient" phases of the famous observe-orient-decide-act loop (OODA loop), or Boyd cycle, as described by the USAF war theorist Col. John Boyd. In combat, the winning strategy is to "get inside" your opponent's OODA loop, not just by making one's own decisions quicker, but also by having better SA than one's opponent, and even changing the situation in ways that the opponent cannot monitor or even comprehend. Losing one's own SA, in contrast, equates to being "out of the loop". Clearly, SA has far reaching applications, as it is necessary for individuals and teams to function effectively in their environment. Thus, SA has gone far beyond the field of aviation to work being conducted in a wide variety of environments. SA is being studied in such diverse areas as air traffic control, nuclear power plant operation, emergency response, maritime operations, space, oil and gas drilling, vehicle operation, and anesthesiology. Theoretical model Endsley's Cognitive Model of SA The most widely cited and accepted model of SA was developed by Dr. Mica Endsley, which has been shown to be largely supported by research findings. Lee, Cassano-Pinche, and Vicente found that Endsley's Model of SA received 50% more citations following its publication than any other paper in Human Factors compared to other papers in the 30 year period of their review. Endsley's model describes