A case study on variability in user interfaces

Software Product Lines (SPL) enable e cient derivation of products. SPL concepts have been applied successfully in many domains including interactive applications. However, the user interface (UI) part of applications has barely been addressed yet. While standard SPL concepts allow derivation of functionally correct UIs, there are additional nonfunctional requirements, like usability, which have to be considered. This paper presents a case study investigating UI variability found in variants of the commercial web-based information system HIS-GX/QIS. We analyze which aspects of a UI vary and to which degree. The results show that just tweaking the nal UI (e.g., using stylesheets) is not su cient but there is a need for more customization which must be supported by, e.g., UI-speci c models.