ABSTRACT
Most interface designs start by first establishing the information requirements. For more complex systems, a structured approach is needed to ensure, first, that all the required information elements are considered and, second, that they are included in the optimal way to ensure an appropriate balance of system values (e.g. safety, efficacy, efficiency, usability and resilience). The approach starts with a list of the information requirements that could be needed by the system. This list is then coded to provide additional detail and constraints, such as when, where, to whom and how information should be displayed. Decision-making is fundamental to safe and effective system control. The decision ladder is the tool most commonly used within cognitive work analysis to describe decision-making activity. Finally, this chapter presents a case study that is based on a generalised description of a radiography machine and describes the high-level task flow for the machine operation.
