What does the Operator do in Complex Systems*

An effort was made to locate representative data on human activities in complex operational systems. Very little operational data were found which were suitable for our purposes. Therefore, this requirement was compromised and activity data from tests and paper and pencil analyses were used. These data were then classified by two raters according to an adopted taxonomy. It was generally concluded that where activity data have been gathered under operational conditions, they have been useful to design engineers, human factors specialists and systems analysts. It is further noted, however, that additional effort must be devoted to the development of better methods for obtaining data and corresponding criteria of human performance under operational conditions. A discussion of the taxonomy and other techniques indicated that collection of activity data should be feasible under operational conditions. In addition it is suggested that increased standardization and use of operational definition in the development of these techniques might result in improvement of their general applicability.