Principles of HCI Design

Don't go to the right?

Where do you plug in the mouse?

Traditional Software Design• Waterfall model of software life cycle

Project Definition

Requirements Specification

Integration and system testing

Coding and Module testing

Functional Design

Module Design

Architecture Design

Operation and maintenance

User Centered Design

• There should not be a black box for the user!

• The User SHOULD– Drive all user interface design

decisions– Determine goals and set priorities– Agree upon all goals that will be used

in designing the user interface

User-Centered Project Life Cycle

User/Task Analysis

I

Set Usability Goals

I

Design Interface

I

Evaluate Designs

IBuild Prototype

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Test Prototype

Test Okay?

Iteration is the key!• No design will be perfect in the first time.• Interactive systems cannot be completely

specified from the beginning of the life cycle.– Users need to be involved all the time.

• Evaluation and testing should be done throughout the design process.– Design and testing should be repeated

iteratively.– Prototypes, rather than real systems, can

be used for testing.

How to Start?

• Intelligent Borrowing– Plagiarizing or Good Design Practice– http://www.freewebtemplates.com/

• Getting to Know Existing Frameworks– Guidelines and standards

• IBM Web Design Guidelines (http://www-3.ibm.com/ibm/easy/eou_ext.nsf/publish/558)

• Ameritech User Interface Standard(shttp:// www. ameritech.com:1080/corporate/testtown/library/standard/index.html)

Getting started

• Getting to Know Existing Frameworks– Convention

• User is already familiar with the process or arrangement from other interfaces

• Most of user interface design requires designers to work within the tight constraints of existing designs

• Studying existing applications– look at systems users already know– Copy interaction techniques

• copy the style of menu selection, organization of screen elements, etc. (where appropriate)

– Understand why design was done in the way it was done with the existing interface

Methods of Iterative Design

• Scenario Generation– Choosing Representative Scenarios

• Comprehensive• Critical Task• Random

• Scenario Validation & Review– Key stakeholders first– Group reviews later

Methods of Iterative Design

• Deriving Storyboards from Scenarios

• Paper Prototyping– Explore constraints– Study standards &

guidelines

Methods of Iterative Design

• Building an interactive rapid prototype from a paper prototype.

• Testing the Prototype with Users.• Iteration Control

– Each iteration has a specific usability goals.

Prototype