Development of A Single Usability Metric that Accounts for Accessibility (SUMA)

Abstract: Various technology tools have been designed to aid person(s) with disabilities (PWD). However, no wholistic, standardized method exists that evaluates usability with a focus on accessibility of apps. The objective of this study was to develop a model to assess app usability with a single usability metric that accounts for accessibility (SUMA). The model includes both subjective and objective usability measures to create a comprehensive view of usability and considers accessibility metrics to ensure interfaces are inclusive for PWD. SUMA combines all measures into a singular score, so it is easily interpretable and comparable to other interfaces since previous studies tended to prefer singular score questionnaires. Seven metrics are selected based on their relevance to website and app design as well as inclusivity considerations for PWD including efficiency, effectiveness, satisfaction, accessibility, learnability, flexibility, and memorability. This paper focuses on the development of SUMA and explains the next steps to finalize the model. This includes reducing model dimensionality through a principal component analysis (PCA) of user testing data from an indoor navigation app designed for PWD. Examples of the final model and Excel package are shown based on the pilot data. The results of PCA yielded a model with reduced dimensionality while maintaining a desirable amount of dataset variability.

Keywords: usability model, accessibility, indoor navigation, interface evaluation

DOI: 10.54941/ahfe1005655

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