Class Meeting 8 November 1, 2005 CSC 8570 -- USI Class Meeting 8 November 1, 2005

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

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

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

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

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.

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

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

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

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

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

Interface Evaluation (2) Measurements Time Counts Geometry Satisfaction

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

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

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

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

Web Site Assignment www.allentownpa.org www.altoonapa.gov www.arnoldpa.org www.bethlehem-pa.gov www.cityofduquesne.com www.yorkcity.org www.cityoferiepa.com www.franklinpennsylvania.net www.harrisburgpa.gov www.cityoflancasterpa.com www.mckeesport.org www.newcastlepa.org www.cityofreadingpa .com www.cityofwilliamsport.org

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

Research Team Meetings