Über die Quantifizierung der beiden software-ergonomischen Richtlinien 'Feedback' und 'Flexibilität'

The main problems of standards (e.g. DIN 66 234, ISO 9241) in the context of usability of software quality are that they cannot measure all relevant product features in a task independent way. The author presents a new approach to measure user interface quality in a quantitative way. First, he developed a concept to describe user interfaces on a granularity level, that is detailed enough to preserve important interface characteristics, and is general enough to cover most known interface types. The author distinguishes between different types. He distinguishes between different types of 'interaction point'. With these kinds of interaction point several types of interface (CUI: command, menu, form-fill-in; GUI: desktop, direct manipulation, multimedia, etc) can be described. The author carried out two different comparative usability studies to validate the quantitative measures. The results of one other published comparative usability can be predicted. Results of six different interfaces are presented and discussed. One of the most important results is that the dialogue flexibility must exceed a threshold of 15 - measured with two of the metrics - to significantly increase the usabilit