Hierarchical task analysis for ergonomics research. An application of the method to the design and evaluation of sound mixing consoles.

Hierarchical task analysis, the procedure originally devised by Annett and his colleagues for determining training needs, was applied to the task of mixing sound in order to identify the human factors requirements that need to be taken into consideration in the design and evaluation of sound mixing consoles. A number of ergonomics problems were identified and potential solutions tentatively suggested. Following the task analysis a comparative simulation study was devised in order to test the hypothesis that the functional grouping of control knobs, with increased spacing between functional groups relative to the spacing within functional groups, is superior to functional grouping per se. Reaction time data strongly support the hypothesis. This suggests that the present practice in mixing console design of arranging control panels so that the components are spaced equidistant or quasi-equidistant, irrespective of their functions, is detrimental to operator performance. The role and importance of task analysis in human factors research is discussed. Hierarchical task analysis is advocated on the grounds that the resulting task description facilitates the systematic identification of ergonomics problems.