The representations that are used to express the design models, e.g. textual notations, graphs and prototypes. This is by no means an exhaustive list of dimensions that are of interest in describing design models. Clearly, the relevance of the various dimensions depends on the context of use of the framework. Different design methods may incorporate one or more of these uses. Note that we are not claiming that the three forms of task model are identical, but that they are used to represent similar information.
Designers can use it to document the users' tasks and to create design solutions.
The model can be used by designers and users for documenting and creating a new work flow and also for critiquing or evaluating an existing system. This shows how design methods can complement each other in their use of models. Unfortunately, this simple example does not show how a more complete set of models could be compared and contrasted. The framework outlined here allows us to describe design methods in terms of the models they employ, irrespective of the design phase for which they are used, providing a basis for comparison of models that use similar information for different purposes. Further, it allows us to identify gaps in the available design methods.