The use of subjective rating.

Abstract To evaluate work load in ATC-tasks the method of subjective rating has been applied in addition to the recording of physiological data and objective work factors. A scoring method and a procedure for observer rating have been used to record variations in the subjective feeling of work load. The results of subjective rating have been related to different measures of information processing. Some problems concerning the influence of individual capacity in the procedure of observer rating for the evaluation of work load and the difficulties in defining ‘ difficulty of the control task ’ are discussed.