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Evaluating system utility and conceptual fit using CASSM

Blandford, A., Green, T. R. G., Furniss, D. & Makri, S. (2008). Evaluating system utility and conceptual fit using CASSM. International Journal of Human-Computer Studies, 66(6), pp. 393-409. doi: 10.1016/j.ijhcs.2007.11.005

Abstract

There is a wealth of user-centred evaluation methods (UEMs) to support the analyst in assessing interactive systems. Many of these support detailed aspects of use – for example: Is the feedback helpful? Are labels appropriate? Is the task structure optimal? Few UEMs encourage the analyst to step back and consider how well a system supports users’ conceptual understandings and system utility. In this paper, we present CASSM, a method which focuses on the quality of ‘fit’ between users and an interactive system. We describe the methodology of conducting a CASSM analysis and illustrate the approach with three contrasting worked examples (a robotic arm, a digital library system and a drawing tool) that demonstrate different depths of analysis. We show how CASSM can help identify re-design possibilities to improve system utility. CASSM complements established evaluation methods by focusing on conceptual structures rather than procedures. Prototype tool support for completing a CASSM analysis is provided by Cassata, an open source development.

Publication Type: Article
Publisher Keywords: CASSM, usability evaluation methods, conceptual structures, co-evolution
Subjects: Q Science > QA Mathematics > QA76 Computer software
Z Bibliography. Library Science. Information Resources > Z665 Library Science. Information Science
Departments: School of Mathematics, Computer Science & Engineering > Computer Science > Human Computer Interaction Design
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