A tool for rapid assessment of product usability and universal design: Development and preliminary psychometric testing

Background: While there are many available tools and methods to evaluate product usability, few have been tested on user groups with disabilities and even fewer systematically consider universal design principles. Objective: This paper describes the development and preliminary psychometric testing of the Rapid Assessment of Product Usability & Universal Design (RAPUUD), a 12-item user-report tool based on the seven principles of universal design. Method: A preliminary set of items was created to elicit ratings of diverse product characteristics (e.g., physical effort, cognitive effort, assistance required, safety). Data were gathered from 61 participants who rated the usability of products they use in their own environments. Results: Each item elicited a full range of responses, with no apparent floor or ceiling effects. Collectively, the 12 items achieved a high internal consistency (Cronbach's α = 0.80). The data indicate that the tool was sensitive to differences in functional abilities, as well as differences in product characteristics. The instrument was usable for a range of consumer products, though not all items were appropriate for each and every product. Conclusion: The results suggest that the instrument could become a pragmatic tool for designers to identify usability problems experienced by a diversity of user populations.