What makes a good test report? A good usability test report tells the reader why and how you conducted the usability test, documents general and specific findings, and provides supporting data. Concise report formats, such as slide presentations, can be an appropriate means to document a formative usability test. We believe an extensively illustrated, narrative format is the best way to document a summative usability test. The goal of any report is to clearly describe the interactive strengths and shortcomings of the evaluated item. Summative usability test reports should pay particular attention to task failures-primarily safety-related use errors-and the associated root causes.