Evidence Based Design of Heuristics: Usability and Computer Assisted Assessment

Abstract

The research reported here examines the usability of Computer Assisted Assessment(CAA) and the development of domain specific heuristics. CAA is being adopted within educational institutions and the pedagogical implications are widely investigated, but little research has been conducted into the usability of CAA applications.

The thesis is: severe usability problems exist in GAA applications causing unacceptable consequences, and that using an evidence based design approach GAA heuristics can be devised The thesis reports a series of evaluations that show severe usability problems do occur in three CAA applications. The process of creating domain specific heuristics is analysed, critiqued and a novel evidence based design approach for the design of domain specific heuristics is proposed. Gathering evidence from evaluations and the literature, a set of heuristics for CAA are presented. There are four main contributions to knowledge in the thesis: the heuristics; the corpus of usability problems; the Damage Index for prioritising usability problems from multiple evaluations and the evidence based design approach to synthesise heuristics.

The focus of the research evolves with the first objective being to determine If severe usability problems exist that can cause users d?ffIculties and dissatisfaction with unacceptable consequences whitct using existing commercial CAA software applications? Using a survey methodology, students' report a level of satisfaction but due to low inter-group consistency surveys are judged to be ineffective at eliciting usability problems. Alternative methods are analysed and the heuristic evaluation method is judged to be suitable. A study is designed to evaluate Nielsen's heuristic set within the CAA domain and they are deemed to be ineffective based on the formula proposed by Hanson et al. (2003). Domain specific heuristics are therefore necessary and further studies are designed to build a corpus of usability problems to facilitate
the evidence based design approach to synthesise a set of heuristics, in order to aggregate the corpus and prioritise the severity of the problems a Damage Index formula is devised.

The work concludes with a discussion of the heuristic design methodology and potential for future work; this includes the application of the CAA heuristics and applying the heuristic design methodology to other specific domains.