The Effect of Task Characteristics on Perceived Usability

Open Access
Kokini, Christina Maria
Graduate Program:
Industrial Engineering
Master of Science
Document Type:
Master Thesis
Date of Defense:
Committee Members:
  • Richard Donovan Koubek, Thesis Advisor
  • perceived usability
  • task analysis
  • usability
  • mental workload
  • control
Product development teams have many factors to consider when designing products, but one of the most important ones is the usability of the product, which contains both objective and subjective components. To have good usability, a product must have attributes such as learnability, efficiency, memorability, reduction of errors, and satisfaction. An important factor in understanding the usability of a product is the context in which the product is being used, which consists of individual characteristics of the users, characteristics of tasks performed with the product, and the environment in which it is used. Though a variety of task analysis methods provide ways for practitioners to systematically study tasks, and usability studies have empirically measured the effects of the users and environment on usability, the literature is lacking empirical studies measuring the direct effect of task characteristics on usability. This study uses a task taxonomy created using the task characteristics approach of classifying human performance to identify specific task characteristics, mental workload imposed by task goal and degree of perceived operator control, which are then varied while the rest of the context and the interface design are held constant and the perceived usability is measured. Main effects for mental workload and perceived control on perceived usability were found to be statistically significant, though the interaction effect was not. These results provide theoretical implications concerning the depth of common task analysis methods, as well as practical implications for product development teams regarding the depth of their analysis of the context of end use and the context in which they conduct their own usability testing.