Abstract
When designing complex systems, it is crucial but challenging to make them easy to learn. In this paper, a framework for improving the learnability of a complex system is presented. A classification of factors affecting the learnability of a building modeling system as well as guidelines that refine the factors into practical ways of action are introduced. The factors and guidelines include issues related to the user interface, conformity of the system to user's expectations, and training. The classification is based on empirical research during which learnability was assessed with several methods. The methodology and the classification of learnability factors can be used as references when analyzing and improving the learnability of other systems. System developers and training providers can utilize these guidelines when striving to make systems easier to learn.