In this volume, the authors begin by defining usability, advocating and explaining the methods of usability engineering and reviewing many techniques for assessing and assuring usablity throughout the development process. They then follow all the steps in planning and conducting a usability test, analyzing data and using the results to improve both products and processes. Using examples from many types of products and tests, the book discusses the full range of testing options from quick studies with few subjects to more formal tests with carefully designed controls. The authors discuss the place of usability laboratories in testing as well as the skills needed to conduct a test. Included are forms to use or modify to conduct a usability test, as well as layouts of existing labs that should help the reader build his or her own.