Modelling Multi-users Tasks

• To improve understanding of the application domain, in this case designers develop task models corresponding to the existing application and the modelling work can stimulate the request of many clarifications whose need may not be perceived just reading textual descriptions or documents; • To support effective design, in this case designers develop an envisioned task model of a new application incorporating requirements received (for example to use some specific technology or to overcome some limitations for end user that occur in current applications) and the various information contained in the new task model can support the design and implementation of a concrete user interface; • To perform usability evaluation, to compare how users interact with an application and the related task model (Lecerof & Paternò 1999) can be useful to understand limitations of the current design, whose improvement may imply changes in the corresponding task model.