CS 66-460
Introduction to Graphical Human Machine Interfaces

The Usability Engineering Lifecycle


Instructor: G. Bowden Wise
Rensselaer Polytechnic Institute
Spring 1997


Usability Engineering

Lifecylce Stages

  1. Know the user
    1. individual user characteristics
    2. the user's current and desired tasks
    3. functional analysis
    4. the evolution of the user and the job
  2. Competitive analysis
  3. Setting usability goals
    1. financial impact analysis
  4. Parallel Design
  5. Participatory Design
  6. Coordinated design of the total interface
  7. Apply guidelines and heuristic analysis
  8. Prototyping
  9. Empirical testing
  10. Iterative design
    1. capture design rationale
  11. Collect feedback from field use

Lifecycle Model

What is Design?

Know The User

Know The User:
Iindividual user characteristics

Know The User: Task Analysis (1)

Know The User: Task Analysis (2)

Know The User: Task Analysis (3)

Know The User: Task Analysis (4)

Know The User: Functional analysis

Know The user:
The Evolution of the User

Competitive Analysis

Goal Setting

Goal Setting (2)

Usability has many different aspects

Normally not all usability aspects can be given equal weight

So we have to prioritize by setting goals for each aspect

Pick levels for each aspect:

Financial impact analysis

Parallel Initial Design

Iterative Design Process

Iterative Design Process (2)

Make a Prototype or partial implementation of the system early and quickly

Redesign the interface based on feedback from evaluation

New design may be worse or may break something else.

Keep track of reasons for design decisions

Iterative Design Process (3)

Implementation Phase:

The Spiral Model


Prototyping (2)

Uses of Prototypes:


Prototype Methods

Prototype Methods (2)


Prototype Methods (3)

PICTIVE = plastic interface for collaborative technology initiatives through video exploration

interactive prototyping using prototyping tools

 Use of the Prototype                 Tools 
 ===================================  =================================
 Working out initial ideas            Paper, SILK 
 Demonstration of the concepts        Paper, Director, Hypercard, VB 
 Experiments with users               Paper, ~Director, Hypercard, VB 
 Release "experimental" version       ~Hypercard, VB, C++ 
 Real, delivered system               C++

Bowden Wise
Tue Feb 25 11:10:04 EST 1997