Originators and proponents: Card, Moran and Newell in 1983; Bonnie John et al.
Keywords: Goals, operators, methods, selection rules
GOMS Model (Card, Moran, and Newell)
This model is the general term for a family of human information processing techniques that attempt to model and predict user behavior. Typically used by software designers, a person’s behavior is analyzed in terms of four components:
- Goals – something that the person wants to accomplish. Can be high level (e.g. WRITE-PAPER) to low level (e.g. DELETE CHARACTER)
- Operators – basic perceptual, cognitive, or motor actions used to accomplish goals, or actions that the software allows user to make (e.g. PRESS-ENTER-KEY or CLICK-MOUSE)
- Methods – procedures (sequences) of subgoals and operators that can accomplish a goal
- Selection rules – personal rules users follow in deciding what method to use in a circumstance
- Task in question must be usefully analyzed in terms of the procedural (how to do it) knowledge.
- Represents only skilled behavior. Not useful for ill-defined problem solving, exploration, etc. Cognitive walkthrough is useful for exploratory behavior by novices.
- Need to start with a list of top-level tasks or user goals. List must be provided outside of GOMS.
- Keystroke Level Model (KLM) by Stuart Card: The first, simplest form of GOMS consisting of the sum of subtasks and required overhead. That is, the sum of the time of P – pointing, H – homing, D – drawing, M – mental operator, R – waiting for system response.
- Card Moran Newell (CMN)-GOMS: A serial stage model of GOMS.
- Critical Path Method (also known as Cognitive Perceptual Motor or CPM-GOMS): A parallel stage model (for users with highest level of skill) critical-path-method or cognitive-perceptual-motor analysis of activity – perceptual, cognitive, motor operators can be performed in parallel as the task demands.
- Card, S., Moran, T., and Newell, A. (1983) The Psychology of Human-Computer Interaction, Lawrence Erlbaum Associates, Hillsdale, NJ. [Book that introduces the GOMS model]
- John, B. and Kieras, D. E. (1996). Using GOMS for user interface design and evaluation: Which technique? ACM Transactions on Computer-Human Interaction (3) 4: 287-319. [Paper explains which GOMS variant to use depending on situation]
- John, B. and Kieras, D. E., (1996). The GOMS Family of User Interface Analysis Techniques: Comparison and Contrast, ACM Transactions on Computer-Human Interaction. (3) 4: 320-351.