Abstract
alert applications can save precious lives in time-critical risk situations; however, even the most widely used applications may fall short in intuitive interface and content design, possibly due to limitations in the users participation in the design process and in the users range considered. The objective of this study was to investigate whether the application of UCD principles and usability guidelines can improve the use of and satisfaction of time-critical weather alert apps by the public and or expert users. A prototype of a UCD-based weather alert application was developed and evaluated. Initially, thirty-two voluntaries participated in the identification of the important features that lead to the development of the porotype, and then the prototype was tested with another eighty participants (40 young and 40 elderly). The prototype includes five enhancements: auto-suggested location search, an all-inclusive interface for weather forecasts, message alert, visual and intuitive map settings, and minimalism-oriented alert settings. The enhanced functionality was compared to similar functionality in existing commercial weather applications. Effectiveness (completion rate, error count, error severity, and error cause), efficiency (time to completion), and satisfaction (post-task and post-test surveys) were measured. The results showed the enhancements significantly improved performance and satisfaction across both age groups compared to equivalent functionality in the existing app. The Mann-Whitney U test showed a statistically significant difference (p < 0.001) in task satisfaction and number of errors between the two apps for all tasks. The Mann-Whitney U test showed a significant difference (p < 0.001) in the across all tasks between the two apps Also, overall, young people with existing apps outperformed elderly, and both young and elderly with enhanced apps performed very high. Therefore, the enhancements implemented through the UCD process and usability guidelines significantly improved performance and satisfaction across both age groups to facilitate timely action necessary during a crisis.