6. Conclusions
This study examined the effectiveness of two methods that are currently used in inclusive design: user trials and exclusion calculations. Both methods were used to examine three autoinjectors. The study found that each method, on its own, failed to identify all the usability problems. In contrast, when used together, the methods complemented each other. Each provided insight that the other lacked, as well as improving the execution of the other method. In particular, the user trials were more effective at identifying unexpected user actions and cognitive issues, while the exclusion calculations were better at identifying problems for people with low capabilities. The calculations also focused attention on the “highest hurdles”: those aspects of product use that really limit the numbers who can use it, no matter how inclusive other aspects are. Together with the population exclusion figures,this can help designers to prioritise design effort where it will really make a difference. The paper also provides recommendations for how the individual methods can be used more effectively in inclusive design. However, the methods should ideally be used together to ensure a wide range of inclusive design issues are covered. More case studies are needed to fully evaluate the contributions of different methods in inclusive design. Further work is also needed to improve and assess the methods based on the study findings. In particular, a survey is being developed to gather data more suited to exclusion calculations (Tenneti et al., submitted for publication). This should particularly improve the examination of cognitive issues, but work is needed to assess its effectiveness in practice.
