This paper presents an investigation of interactive worksystem planning in the multiple task work domain of medical reception. In an observational study of a medical reception worksystem, three different types of plan were identified: the task plan, the procedure plan and the activity plan. These three types of plan were required for effective working in the domain of medical reception, because of the many similar concurrent tasks, the frequency of behaviour switching between tasks and the need for consistency within the worksystem. It is proposed, therefore, that to design effective interactive human-computer worksystems for the domain of medical reception (and possibly for other work domains of a similar nature), the designer must specify the three different types of plan and the relationships between them. The three types of plan in medical reception are discussed in the context of design issues such as the allocation of planning structures
