Evaluating accessibility through simulating the experiences of user users with vision or motor impairments

User studies involving users with disabilities often incur greater financial cost and complexity than those involving general populations. One consequence of this is that accessibility issues may not be identified during the earlier phases of design, when designs are still malleable. Additionally, it can be difficult to create controlled studies with multiple groups of very similar subjects due to the extremely heterogeneous nature of the impact of many motor and visual disabilities. This paper examines the feasibility of simulating the interaction experiences of users with low vision and/or motor impairments. We developed a tool, EASE (Evaluating Accessibility through Simulation of User Experience), based on empirical studies in the literature of the impact of these impairments on the experience of computer use. EASE can help developers identify disability-related usability problems early in the design process. EASE can also be used to allow fine grained exploration of user capabilities that are difficult to account for, such as typing speed. We present a study of the use of word prediction software, illustrating the value of fine-grained control over typing speed, and showing that word prediction is most useful at typing speeds between 5 and 8 words per minute.