summative and formative evaluation of software
Günther Gediga & Kai-Christoph Hamborg
Fachbereich Psychologie, Universität Osnabrück, Germany
The IsoMetrics usability inventory provides an user-oriented, summative as well as formative approach in software evaluation on the basis of ISO 9241 Part 10. The summative version of IsoMetrics (IsoMetricss) gathers valid information about differences in the usability of software systems. Moreover the formative version of IsoMetrics (IsoMetricsL) is a tool for supporting the identification of software weaknesses.
The actual version of IsoMetrics comprises 75 items operationalizing the seven design principles of ISO 9241 Part 10. The statement of each item has to be assessed on a five point rating scale starting from 1 (,,predominantly disagree") to 5 (,,predominantly agree"). A further category (,,no opinion") is offered to reduce arbitrary answers. IsoMetricsL consists of the same items as IsoMetricss and uses the same rating procedure. Additionally, each user is asked to give a second rating, based upon the following request:
"Please rate the importance of the above item in terms of supporting your general impression of the software."
This rating ranges from 1 (,,unimportant") to 5 (,,important"), and a further ,,no opinion" category may also be selected. Thus, each item is supplied with a weighting index.
To evoke information about malfunctions and weak points of the system under study, the question: