1. Class Meeting 8 November 1, 2005
CSC USI
Class Meeting 8
November 1, 2005

2. Important Concepts
Models of physical action: Fitt’s Law, Hick’s Law, Keystroke Level Model
GOMS model, in various forms
Cognitive dimensions of notation
What makes a good interface? Who says?
GUEPs
Mental models, in various forms

3. Important Concepts (2) Applied perception
How humans perceive their surroundings
Usability models
That metrics for interfaces exist
Simple interfaces are best
Making better concept maps

4. Confusions – Mental Models
As theories
How one believes a system works, e.g. an ATM machine, a history list
As problem spaces
A set of partial solutions to a problem with transitions from one partial solution to the next, e.g. the “screen shots” as you solve a Sudoku puzzle

5. Mental Models (2) As homomorphisms of the physical world
An analog picture of a description from which inferences may be drawn
Derived from language, perception, or imagination
The image, or pictorial context, drawn from a textual description

6. Mental Models (3)
As representations of representational artifacts (yoked state space)
A combination of the goal space and the operations available to transform the elements of the goal space. The model one uses when editing text or creating a webpage in a text editor.

7. Mental Models (4)
As computationally equivalent to external representations (internalization)

8. Confusions – GOMS
Match GOMS to the problem space view of a mental model
Compare GOMS and the KLM for a system
Develop two or three clear examples
Clock setting
Route discovery
POS credit card payment

9. Confusions – Others Cognitive dimensions
Models and frameworks in general
Which are better
Which are more important
Three-stage visual model
Preparing for the exam

10. Button Experiment Button syntax Button semantics
Notation
Button semantics
Properties of buttons
Button class
Cognitive dimensions of the button
GUEPs supported/violated by the button

11. Interface Evaluation Models and techniques GOMS analysis
Keystroke Level Model
Cognitive dimensions of notation
Hierarchy of design principles
Task analysis
Layout appropriateness

12. Interface Evaluation (2)
Measurements
Time
Counts
Geometry
Satisfaction

13. Interface Evaluation (3)
Musike Scoring System
Developed for menu-based systems
Modified for web pages
Provides weighted sum of scores of individual factors
Each individual factor to be based on a measurable design principle

14. Example -- AWSP Evaluates web sites
Based on Jakob Neilsen’s design principles
Rewritten by Lea Taylor

15. AWSP Definitions
Above the Fold: The first screen content that is visible without scrolling
Examples: Content that provides insight into the results of following a link
External Ads: Ads for companies or organizations other than the focus of the current website

16. AWSP Definitions (2)
Liquid Layout: Layout that allows the text to adjust to the size of the available space
Widget: A simple interface feature such as a dropdown menu or a text box

17. Web Site Assignment www.allentownpa.org www.altoonapa.gov
.com

18. Next Time
Read Carroll, Chapter 10.
Create concept map for Chapter 10

19. Research Team Meetings