ABSTRACT
This chapter discusses some general problems in the development of taxonomic systems applicable to descriptions of human performance and tasks. It illustrates some specific measurement and scaling techniques applicable to certain task classification systems and evaluates their reliability. The chapter attempts to evaluate the utility and validity of these systems. It also describes specific attempts to apply certain task classification systems to several areas of human performance research. The chapter emphasizes that despite the differences among specific tasks in terms of equipment, displays, and response requirements, the classification system enabled an integration of results and the development of functional relationships that were otherwise obscured. It explores the consequences of the foregoing rationale for development and use of a task descriptive system by constructing an heuristic model of performance. The development of task characteristics received initial guidance from a definition of the term 'task' which was devised early in the project.
