Introduction Digital technologies improving clinical outcomes and efficiency are prioritized for development. We have developed a musculoskeletal Digital Assessment Routing Tool (DART) directing users to right care, first time. DART requires usability testing prior to clinical trials.

Materials and Methods An iterative-convergent mixed-methods design was used to assess and mitigate DART usability issues. 22 participants used 50 musculoskeletal presentations across 4 DART iterations during 5 testing rounds. Recruitment quotas for age, habitual internet use and English language ability were used. Constructs of the ISO 9241-210-2019 standard defined quantitative data collection, with user satisfaction measured by the system usability scale. Study endpoints were mitigation of significant usability problems and a mean satisfaction score of 80+ across a minimum of 3 testing rounds.

Results All test assessments gave a recommendation with no system errors. Usability problems reduced from 12 to zero. Mean assessment time was 5 minutes (range 1–18), 6 minutes for non-native English speakers. Differences in satisfaction scores were present between groups, expert internet users having the highest mean score (86.5, SD 4.48, CI 90% 1.78), compared with non-native English speakers (78.1, SD 4.60, CI 90% 9.17) and less experienced internet users scoring the lowest (70.8, SD 5.44, CI 90% 3.79). The mean score across all groups was 84.3 (84.3, SD 12.73, CI 90% 4.67), with qualitative data from all participants confirming DART was simple to use.

Conclusion With all significant usability problems addressed DART can proceed to a randomized controlled trial assessing safety and effectiveness against a usual care comparator.