  Cognitive Work Analysis (CWA): An integrated approach to human-centered system design developed primarily by Rasmussen and described in Vicente's Cognitive Work Analysis book. The approach is divided into five stages: Work Domain Analysis, Control Task Analysis, Strategies Analysis, Social Organization and Cooperation Analysis, and Worker Competencies Analysis. While this approach is broad in the scope of its analysis activities, its primary focus is on the work domain.
The work domain imposes fundamental constraints on behavior that any agent, be they human or machine, must satisfy for success. The complexity of behavior that arises in performing work tasks is not a function of the complexity of the agent, but rather a function of the complexity of the world. The work domain is modeled as an Abstraction Hierarchy (AH), which shows goal-means relationships on different levels of the hierarchy, including functional purpose, abstract function, generalized function, physical function, and physical form.
The AH shows how higher level functions (such as mission goals) may be supported by lower level functions and physical systems (such as sensor systems). It can show how the same physical system can support multiple higher level functions. The Work Domain Analysis Workbench (WDAW) is a software tool currently under development to support system development using CWA. references: see http://mentalmodels.mitre.org/cog_eng/ce_references_V.htm#cwa 
