A walkthrough facility for testing the usability of a user interface design before the software is written or a prototype is built is described. The use of this method to evaluate screen panels, which may include pull-down menus, dialogue boxes, palettes, and other interface elements, is reported. These pluralistic usability walkthroughs have four characteristics. First, three types of people participate in the walkthrough: representatives of the expected user population, product developers, and human factors professionals. Second, the user interface panels are presented in the same order they would be confronted online. Third, participants write down their responses on each panel before there is any discussion. Finally, the representative users speak first when discussing the panels and the experts speak only when the users have exhausted their comments. The limitations and benefits of the walkthrough approach are examined.