About R&Q's Case Studies: We hope you enjoy our latest case study. View all of our available Case Studies. Subscribing to our blog is the best way to know when future case studies are available. FDA Approved: Creating and Implementing a Compliant Usability Engineering Process Challenge PMA supplement for usability updates not approved. A medical device manufacturer made an update to the design of their Class III device to improve usability and promote proper care and maintenance, and they submitted a PMA supplement to the FDA for the changes. The PMA supplement included a human factors test report from a usability study intended to demonstrate the effectiveness of the changes. The company received a letter from the FDA expressing concern with the level of evidence provided by their human factors testing. The FDA noted that the recent usability study had focused on ease of handling rather than comprehensive safe and effective use, engaged company employees as study participants rather than unaffiliated representative users, and failed to demonstrate that risks related to the most critical aspects of device use had been appropriately addressed in the design and evaluated in testing. The FDA requested that the client conduct another human factors study that addressed these concerns, validating safe and effective use of the device by intended users.