Usability testing is widely used for measuring a system's usability, particularly in relation to websites. It consists of a number of variables such as tasks, number of users, usability measures and other elements. Each variable can influence the usability testing results either negatively or positively. This research investigates the impact of task design upon usability testing results and further examines the role of the number of users in such testing. In addition, usability measure correlations are also explored. In order to achieve these objectives, three experiments were conducted; the first examines the proposal that task design can seriously influence usability testing results. It explores the way in which three different types of task affect these results, the types being: structured, uncertain and problem-solving. Each type of task seems to reveal different types of associated problems. Subsequently, user numbers and usability measures are also examined. In light of the first experiment's results, the second experiment's objectives investigate how a mixed set of different task types can influence the usability testing results concluding again with an examination of user numbers and usability measures. The third and final experiment validates the results of the previous two experiments by examining the influence of task order on usability testing results. The first experiment designed to investigate the influence of task type on usability testing results, involves 5 tasks all performed by 20 users for each of 3 groups. The usability testing results differ significantly. Each type of task reveals certain types of problems, and each one performs differently. In this experiment, "five users" fail to achieve what was promised i. e. the identification of 85% of usability problems. This experiment raises questions and suggests a number of recommendations, such as that tasks should be mixed in usability testing in order to offer better results: these the objectives for the 2 "d experiment. The second experiment investigates the influence of a mixed set of different task types on usability testing results. The three types of tasks above form a set of tasks to be performed by a single user or by a group of users. The participant number is increased to 30 users, who performed 10 tasks. The results show that performing a mixed set of tasks by a group of users can offer better results. In this experiment, "five users" again fail to achieve satisfactory results. This experiment suggests that task order may influence usability testing results, a question addressed in the final experiment's design. In the third experiment; therefore, the tasks are ordered differently to previous experiment. However, this is shown to have no influence on the usability testing results, although does reveal some interesting effects on users behaviour during the performance of such tasks
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:533712 |
| Date | January 2010 |
| Creators | AlShamari, Majed Aadi |
| Publisher | University of East Anglia |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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