Many aspects of usability testing has been thoroughly studied and documented. This is not true, however, from the details of interacting with test participants who provide the critical usability data. This omission means that there are training materials and no principles from which new moderators can learn how to interact. Moderating Usability Tests is the place for new and experienced moderators to learn about rules and practices for interacting that have never been described in one place before. Author Dumas and Loring utilize their combined 40 years of usability testing experience to develop and present the principles of the most effective and practical - both practical and ethical - for a successful usability test moderator. To help usability professionals, students, and students understand these principles, the authors provide videos from their laboratory showing the interaction of good and bad as well as comments from the panel of expert examination of why certain techniques succeed or fail. Moderating show good and bad techniques with laboratory videos accessible from the publisher website companion