How many testers are needed to assure the usability of medical devices?

作者：Borsci Simone^*; Macredie Robert D; Martin Jennifer L; Young Terry

来源：Expert Review of Medical Devices, 2014, 11(5): 513-525.

DOI：10.1586/17434440.2014.940312

• evaluation cohort
• five-user assumption
• medical devices
• product safety
• usability testing

Before releasing a product, manufacturers have to follow a regulatory framework and meet standards, producing reliable evidence that the device presents low levels of risk in use. There is, though, a gap between the needs of the manufacturers to conduct usability testing while managing their costs, and the requirements of authorities for representative evaluation data. A key issue here is the number of users that should complete this evaluation to provide confidence in a product%26apos;s safety. This paper reviews the US FDA%26apos;s indication that a sample composed of 15 participants per major group (or a minimum of 25 users) should be enough to identify 90-97% of the usability problems and argues that a more nuanced approach to determining sample size (which would also fit well with the FDA%26apos;s own concerns) would be beneficial. The paper will show that there is no a priori cohort size that can guarantee a reliable assessment, a point stressed by the FDA in the appendices to its guidance, but that manufacturers can terminate the assessment when appropriate by using a specific approach - illustrated in this paper through a case study - called the %26apos;Grounded Procedure%26apos;.

• 出版日期2014-9