Scenarios can help remedy the most serious obstacle in the design process that is a chronic lack of knowledge of the application domain. Moreover, scenarios can be employed in analysis and design to serve both illustrating the context of an envisaged usage (user's perspective) and demonstrating the design proposal in terms of the intended usage (analyst's perspective). In contrasting both perspectives by means of a dialectic process a synthesis can be achieved that incorporates a shared understanding. Validation is a process to achieve such an understanding. The semantic structure of types of scenarios is investigated thus illustrating how a context of use analysis according to ISO 9241-11 can be exploited for validation purposes. The role of scenarios in usability engineering is contrasted with traditional concepts of systems analysis as an attempt to narrow the bridge between software engineering and usability engineering.

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User-perceived quality of interactive systems is defined in terms of statistically nonoverlapping categories, so-called dimensions or factors Categories are identified by factor analysis and represent a dimensional concept of the quality of interactive systems as perceived by its users. Each category describes essential user requirements.