Assessing usability of eHealth technology: A comparison of usability benchmarking instruments

•Task completion is the best predictor for usability issues in eHealth.•The SUS is not suitable as a stand-alone usability benchmarking tool for eHealth.•Task completion time and the SUS correlate equally to critical usability issues. It is generally assumed that usability benchmarking instruments are technology agnostic. The same methods for usability evaluations are used for digital commercial, educational, governmental and healthcare systems. However, eHealth technologies have unique characteristics. They need to support patients’ health, provide treatment or monitor progress. Little research is done on the effectiveness of different benchmarks (qualitative and quantitative) within the eHealth context. In this study, we compared three usability benchmarking instruments (logging task performance, think aloud and the SUS, the System Usability Scale) to assess which metric is most indicative of usability in an eHealth technology. Also, we analyzed how these outcome variables (task completion, system usability score, serious and critical usability issues) interacted with the acceptance factors Perceived benefits, Usefulness and Intention to use. A usability evaluation protocol was set up that incorporated all three benchmarking methods. This protocol was deployed among 36 Dutch participants and across three different eHealth technologies: a gamified application for older adults (N = 19), an online tele-rehabilitation portal for healthcare professionals (N = 9), and a mobile health app for adolescents (N = 8). The main finding was that task completion, compared to the SUS, had stronger correlations with usability benchmarks. Also, serious and critical issues were stronger correlated to task metrics than the SUS. With regard to acceptance factors, there were no significant differences between the three usability benchmarking instruments. With this study, we took a first step in examining how to improve usability evaluations for eHealth. The results show that listing usability issues from think aloud protocols remains one of the most effective tools to explain the usability for eHealth. Using the SUS as a stand-alone usability metric for eHealth is not recommended. Preferably, the SUS should be combined with task metrics, especially task completion. We recommend to develop a usability benchmarking instrument specifically for eHealth.