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CN04: Designing a Task-Focused Conceptual Model

Quick Facts

Time: Monday, 12 April 2010, 11:30 to 13:00
Units: 1
Organizers: Jeff Johnson


After completing this class, participants will:
  • Know the benefits of designing a task-focused, coherent conceptual model of an application before designing the application’s user interface.
  • Understand the components of a conceptual model (e.g., object-action analysis), and how to create them.
  • Have experience in designing a conceptual model for a software application.


Software designers and developers of all experience levels. Also: usability testers and managers.


Presented at UPA 2007 and CHI 2009.


An important early step when designing a software user interface is to design a coherent, task-focused conceptual model. Unfortunately, many designers start sketching and prototyping the UI before they understand the application at a conceptual level. The result is incoherent, overly-complex applications that expose concepts unrelated to users’ tasks. This course covers:
  • What conceptual models are, and how they improve the UI design process,
  • Perils and pitfalls of skipping a conceptual model,
  • Object/actions analysis,
  • Deliverables of Conceptual Analysis: object taxonomy, lexicon, task scenarios, object-model,
  • A hands-on exercise in performing Object/Actions analysis for a simple application.


Jeff Johnson is Principal Consultant at UI Wizards, a product usability consulting firm. He has worked in HCI since 1978. After earning B.A. and Ph.D. degrees in cognitive psychology from Yale and Stanford, he worked as a UI designer/implementer, usability tester, manager, and researcher at Cromemco, Xerox, US West, Hewlett-Packard, and Sun. Since 1996 he has been a consultant and an author. He has published numerous articles and chapters on HCI. He wrote the books GUI Bloopers, Web Bloopers, and GUI Bloopers 2.0. His forthcoming book, Designing with the Mind in Mind, introduces perceptual and cognitive psychology to software developers. Instructor website: http://www.uiwizards.com