Proxy Users for Usability Testing of Medical Devices for Use in Sub-Saharan Africa

Medical device implementation in global health requires careful considerations around usability and the use of proxy user groups. Working with appropriate proxy users can address the cost burden of conducting international studies with target users. This study evaluated whether proxy users are a practical substitution for conducting usability testing on devices for implementation in low-resource international settings. Identical usability studies were conducted with 18 clinicians from Blantyre, Malawi, and a carefully selected proxy group of 13 clinicians from Houston, Texas, U.S.A., across seven newborn-focused medical devices. Task success rate, System Usability Scale (SUS) scores, and NASA-Task Load (NASA TLX) scores from the two groups were compared. No significant differences were found between groups other than NASA-TLX temporal demand sub-scale, showing it is possible to use a carefully selected proxy group for usability evaluation in international settings. However, there was no consistent agreement between the groups on a task level, indicating that proxy groups should be used with an abundance of caution. Studies with target users must be additionally conducted to confirm results. Further work needs to be done with a larger sample size to test the viability of a proxy group for international studies on medical devices.