Over the years the software engineering community has increasingly realized the important role software architecture plays in fulfilling the quality requirements of a system. The quality attributes of a software system are, to a large extent determined by the system's software architecture. In recent years various tools and techniques have been developed that allow for design for quality attributes, such as performance or maintainability, at the software architecture level. We believe this design approach can be applied not only to non-operational quality attributes such as performance or maintainability, but also to operational quality attributes such as usability. This paper presents and describes a scenario based assessment method to assess whether a given software architecture (provided usability) meets the usability requirements (required usability).