2.2 High-Level Theories

Explanatory theories:

• Observing behavior
• Describing activity
• Conceiving of designs
• Comparing high-level concepts of two designs
• Training

Predictive theories:

• Enable designers to compare proposed designs for execution time or error rates.

Perceptual or Cognitive subtasks theories

• Predicting reading times for free text, lists, or formatted displays

Motor-task performance times theories:

• Predicting keystroking or pointing times

Taxonomy (Explanatory theory)

• Order on a complex set of phenomena
• Facilitate useful comparisons
• Organize a topic for newcomers
• Guide designers
• Indicate opportunities for novel products.