Rohde, Markus (1995): The Scenarionnaire - Empirical Evaluation of Software- ergonomical Requirements for Groupware. In: Preceedings of the HCI International '95, 6th International Conference on Human-Computer Interaction in Yokohama, Elsevier Science Publishers, Amsterdam, 333-341. The Scenarionnaire - Empirical Evaluation of Software-ergonomical Requirements for Groupware Markus Rohde Institute for Computer Science, University of Bonn Römerstraße 164, 53117 Bonn Tel: 0228/550-276, e-mai: markus@uran.informatik.uni-bonn.de 1 Software-ergonomical requirements for groupware We define groupware as systems which offer technical support for communication and cooperation. Computer networking is characterized by structures and processes of interaction. When we speak about computer supported or mediated work we suppose that there are always several persons affected by the usage of certain functions in different ways. If someone activates a special function, he is called the activator; other persons, for whom the usage of this function means any effect, are called users affected. It is obvious that in network interaction regarding the actual usage of specific functions often different and probably conflicting interests will occur. In an explorative study in 1992 we found out that these conflicts of interest often come up with the systems controllability. A person who has got the possibility to choose between several technical options has got controllability of his own workspace and instruments. In network system this controllability often affects other users, who have not got any opportunity - to see, which function was activated and by whom this function was activated - or even to intervene against it. In this understanding controllability means a restriction for the autonomy of a user affected, whose environment is technically manipulated by anybody else's usage of a certain groupware function (Herrmann et al. forthcoming). To reduce these kinds of conflict between users we developed the two following metafunctions, which should be applied to controllability in groupware-systems (Wulf 1993): - Visibility of use gives informations about the behaviour of other active users in the network to the user affected. This metafunction has been developed to enable the users affected to understand what happens to them in a network system. Visibility of use means a restriction in the autonomy of the activator, whose behaviour will become visible for others. Beyond that, it means an increase of situational control for the user affected regarding the actual interaction. - Negotiability as a metafunction means even harder restrictions for the autonomy of the activator. Every activation of certain functions which will or could affect other users has to be negotiated between the partners in interaction. Negotiation requires visibility of use. Every user will be informed, if anybody tries to use a specific function, which could possibly affect him as a participant of the network system. This user affected now has got the opportunity to intervene against this usage. The activator has got the opportunity to insist on his need to activate a special function, when he notices the protest of a user affected, e.g. by explaining the reasons or necessity for the usage. The affected user can accept/ deny the planned activation or suggest a modified activation (e.g. of another optional usage). If there is not found any consensus, the system will automatically activate a default option. Thus, negotiability distributes the situational control of interactional relationship between the both partners in interaction. 2 The scenarionnaire as a method of evaluation