Software Usability By: Robert J. Remington EEL6883 – Software Engineering II Dr. Turgut – University of Central Florida Presented By: Adam Radwan 19 February 2007

Introduction Initial thoughts –Frequently software engineers would like to know if there are any good resources and documentation for designing a good GUI –No magic bullet in design, rather there is a set of rules and suggestions outlined in SWEBOK –IBM Report: 42% of users avoided ordering from the web when presented with a poorly designed user interface

Software Quality Six ISO Standard high-level characteristics to describe software quality –Functionality –Reliability –Efficiency –Maintainability –Portability –Usability

Usability Usability definition: “characteristics relating to the effort needed for use, and on the individual assessment of such use, by a stated or implied set of users” Discussion: What does this definition actually mean? Do the users have any implied prerequisites for system use?

Usability Five characteristics –Understandability –Learnability –Operability –Attractiveness (misspelled in the article) –Compliance to application-related standards, conventions, regulations in law, and protocols

Usability Engineering (UE) Human-Computer Interaction (HCI) mismatches have caused fatal mistakes –Casey (Santa Barbara, CA ’93) reports a case where a radiotherapy accelerator proton beam delivered a lethal 25 M eV as a result of a poorly designed, buggy user interface Usability Professionals Association (UPA) formed at ACM SIG-CHI ’92 by 30 delegates; now over 2000 members

UPA resources Body of Knowledge spans studies done at 63 research and development centers Over 350 articles and laboratory reviews Human-Computer Interaction journal publishes many up-to-date articles As a result, UE has expanded its process models, design standards, and evaluation methodology all combines into user- centered development (UCD)

User-Centered Development UCD process (ISO 13407) lists 4 activities undertaken during a project 1.Understand and specify the context of use 2.Specify the user and organizational requirements 3.Produce design solutions 4.Evaluate designs against requirements

Usability Design Standards ISO 9241 lists standards and guidelines for: –Displayed colors –Dialog principles –Presentation of information –User Guidance –Menu Dialogs –Form-filling Dialogs

Rapid Prototyping Creation of a limited, functional user interface for a “test drive” proven effective Allows for feedback to be obtained in earlier stages of development Helps avoid errors resulting in design problems from miscommunication about user requirements

Software Usability Evaluation Evaluation should take places at all stages of development Research centers often use laboratories with one-way mirrors, microphones, and cameras to monitor how a user may interact with a system for the first time Fitted curve can estimate the number of problems uncovered based on the number of evaluated users 5 users usually uncover approx. 80% of errors

Future Challenges Web-based user interfaces have been a limiting factor compared to traditional GUI development Smaller display size and limited input of mobile applications are current drawbacks with many portable implementations Some systems for I/O and control may best be kept on larger form-factor equipment

Summary No single proven technique for development of high-usability software Usability Engineering becoming more advanced, contributions have increased overall software product quality Further HW/SW advances may solve some known limitations and drawbacks

Questions? Any questions? Time permitting, brief navigation to several websites displaying examples of usability