Testing usability metrics with underserved populations

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
Perustieteiden korkeakoulu | Master's thesis
Software and Service Engineering
Degree programme
Master’s Programme in Computer, Communication and Information Sciences
Digital services underlie many aspects of everyday life, yet they are often not designed to meet the needs of everyone who may need to use them. Optimizing for usability, especially with historically underserved groups, ensures that as many users as possible can benefit from these services. Techniques such as participants thinking aloud in laboratory-based usability testing aim to understand the issues affecting the experiences of users, while self-administered questionnaires, like the System Usability Scale (SUS) provide users with a way to articulate and provide quantitative feedback about their experience. It is not yet clear to what extent these methods are suitable for users with intellectual disabilities and those who speak the language of the questionnaire non-natively. This thesis presents a mixed-methods study in which a redesigned digital health service produced in the Finnish public sector was tested with participants from these groups in a laboratory using the think-aloud technique. It then aims to establish whether three self-administered usability measures capture accurate, comparable measures of these users’ experiences and compare these measures to the observations of the tests. Additionally, any specific elements of the service that are especially challenging to participants are identified and used to propose good practices that can be followed when developing services for these groups. Several specific issues are identified, including participants accepting default options without properly considering them and large, prominent interface elements distracting users. The usability scores studied all showed similar patterns, however answers by the non-native Finnish speaking participants were often inconsistent. Based on the results, all studied usability measures seem to work appropriately for participants with intellectual disabilities, though their results may not compare with other users directly. The results with non-native Finnish speaking participants are so varied that their use cannot be recommended without further research.
Kujala, Sari
Thesis advisor
Kujala, Sari
usability, accessibility, intellectual disability, cognitive accessibility
Other note