At a simple level, situational awareness (SA) is "knowing what is going on around you. Inherent in this definition is knowing what is important." Much of the pioneering work has come from aviation, and indeed many definitions tend to be discipline-specific and operationalized in terms of the ability to perform some task, such as piloting an airplane in bad weather.
There is an increasing trend to separate the product of SA, the operational definition, from the process of SA, the acquiring and processing of information. "In terms of aviation processes and products, ‘the process of SA refers to how SA is developed and maintained during flight, while the product is the resultant, elusive thing we call SA itself.’" Information overload is one way in which SA is lost. The related work of John Boyd deals with the use of situational awareness in the OODA loop; when one combatant "gets inside the OODA loop" of the other, that combatant has greater situational awareness and the ability to make decisions on it.
- M.R. Endsley (2000), Theoretical Underpinnings of Situational Awareness: A Critical Review, in M.R. Endsley and D.J. Garland, Situation Awareness Analysis and Measurement, Lawrence Erlbaum Associates
- C. Dominguez (1994). "Can SA be defined?" In Situation Awareness: Papers and Annotated Bibliography(U). Armstrong Laboratory, Wright-Patterson Air Force Base