The role of task analysis in capturing requirements for interface design.

Recently, the role of task analysis in design has been brought into question. It has been argued, for example, that task analysis leads to the non-creative redesign of existing artefacts. In this paper. we offer a view of task analysis that resolves this problem. In particular, we argue that by focusing upon the analysis of user/operator goals rather than an existing task implementation, task analysis encourages novel and apt design. A reformulation of hierarchical task analysis is offered, based on the sub-goal template (SGT) scheme. The SGT scheme provides a notation for goal-oriented task analysis and defines an appropriate level at which task analyses can inform the design process without constraining it to existing task implementations. The SGT scheme is compared with the systems analysis-based design methodology SSADM and the advantages of each approach are reviewed