Multi-Layered User Interface Design

Licentiate thesis, 2005

In this thesis work we focus on further developing and redefining an interface design concept especially adapted to consider the needs and the knowledge level of many individual users, at once taking the tasks they perform and their learning into careful consideration. The design concept, called Multi-Layered Design (or a Level-structured approach, sometimes even called a spiral approach), was first suggested by Ben Schneiderman in 1998 and then further explored during 1999 to 2003. Based on the previous work, we have continued to investigate the possibilities and the limitations of the concept in close collaboration with end users. By splitting the application interface into components or layers Multi-Layered Design (MLD) can provide the individual users with functions organized in a logical order to promote personal learning in steps. The users move through the layered structure as it suits them best. Simple and common functions are placed in the first layer, and the remaining number of functions and objects are then sorted into the higher layers. The last layer has full functionality and contains all of the functions the application holds. To fit different types of applications the layered structure can be built in many ways and vary in flexibility and complexity. Striving for an improved interface design by using the concept of MLD, we set the goal to define a user-centered interface design with an improved and more effective ability for personal learning through decreased complexity in the interface and sequential learning structures, keeping the necessary additional effort in the application development phase to a minimum. Practical case studies have been performed to further investigate the MLD concept and to explore benefits and drawbacks. With related work as well as our own practical work as a foundation, we draw the conclusion that a formal model is needed to decide the suitable number of layers and layer contents used in MLD. To partially meet this need, we introduce a strict model for how to analyze the user characteristics. The model describes how to depict user characteristics, analyze connections and finally how to divide application interfaces into layered structures based on information about the user. We present five papers illustrating the benefits and drawbacks of the concept of Multi-Layered Design, practical examples, our new theoretical framework, a new model for how to create principles for layer structured design, and finally two practical case studies on how to apply the model.