Book excerpt: Since the publication of the first edition, the FDA and other regulatory groups have modified their regulations and expectations regarding how medical device manufacturers should approach usability testing. Reflecting these changes, this second edition provides updated guidance to medical device manufacturers and other interested readers. Key updates include new requirements, detailed instructions for linking usability test tasks to risk analysis results, and methods for analyzing root causes of use errors that occur during usability tests. The book’s authors are well-known thought leaders in the medical device industry.