esign an ser mterrace Evaluation TheOpen University DEBBIE STONE The Open University, UK CAROLINE JARRETT Effortmark Limited

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1 ser mterrace Evaluation esign an DEBBIE STONE The Open University, UK CAROLINE JARRETT Effortmark Limited MARK W O O D R O F F E The Open University, UK SHAILEY MINOCHA The Open University, UK 9 TheOpen University Mi- К AMSTERDAM BOSTON HEIDELBERG LONDON NEWYORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORTE SYDNEY TOKYO ELSEVIER Morgan Kaufmann Publishers is an imprint of Elsevier. MORGAN KAUFMANN PUBLISHERS

2 Figure Credits xxi Preface xxiii Part 1 Introducing User Interface Design 1 1 Introduction 3 1. Why the User Interface Matters 3 2. Computers Are Ubiquitous 3 3. The Importance of Good User Interface Design What Is a Good User Interface Design? The Problems of Poor or Bad User Interfaces Safety and the User Interface Elections and the User Interface Designing for Users User-Centered Design The Classic Life Cycle Involving Users Making the Design Process Interative The Two Types of Knowledge Needed for UI Design Evaluation When and How Do You Evaluate? Summary 24 Part 2 Requirements 25 2 How to Gather Requirements: Some Techniques to Use Introduction Observing Your Users Direct Observation Indirect Observation: Video Recording Points to Consider in Relation to Observation Interviewing Your Users Points to Consider in Relation to Interviewing Questionnaires and Surveys Types of Question Structure Points to Consider When Designing Questionnaires Summary 36

3 Finding Out about the Users and the Domain Introduction Users: Finding Out Who They Are Describing the Users: Users Have "Characteristics" That Are Relevant to UI Design Designing for Physical Limitations User Profiling: Describing Your Users and Their Characteristics Smaller User Groups Are Easier to Design For Personas: Another Way to Describe Your Users Other Stakeholders Users'Needs: Finding Out What Users Want The Domain: What Expert Knowledge Is Relevant to the Application? Understanding the Domain Representing the Domain Summary 55 4 Finding Out about Tasks and Work Introduction: Describing Users'Work Goals, Tasks, and Actions Task Analysis Mental Models Environmental Considerations: Where Is This Work Done? The Physical Environment: Is This a Pleasant Place to Be? The Safety Environment: Is This a Safe Place to Be? The Social Environment: Do People Help Each Other? The Organizational Environment: Does Management Support This Work? The User Support Environment Consideration of Environmental Aspects and How They Affect Design Summary 87 5 Requirements Gathering: Knowledge of User Interface Design Introduction: The Two Types of Knowledge Needed for User Interface Design Four Psychological Principles Users See What They Expect to See Users Have Difficulty Focusing on More Than One Activity at a Time It Is Easier to Perceive a Structured Layout It Is Easier to Recognize Something Than to Recall It Three Principles from Experience: Visibility, Affordance, and Feedback The Principle of Visibility: It Should Be Obvious What a Control Is Used For 97

4 3.2 The Principle of Affordance: It Should Be Obvious How a Control Is Used The Principle of Feedback: It Should Be Obvious When a Control Has Been Used Design Principles and Design Rules: Knowledge for User Interface Design Summary Thinking about Requirements and Describing Them Introduction Usability Requirements Early Views of Usability The Modem-Day View of Usability Constraints and Trade-offs in Relation to Requirements Gathering Costs/Budgets/Timescales Technical Constraints Trade-offs Problems with Requirements Gathering Requirements Specification Prototyping Purposes of Prototyping: Why Bother Trying Out Your Ideas? Low-Fidelity Prototypes High-Fidelity Prototypes: Using Software Tools to Try Out Your Ideas Cautions about Prototyping Summary Case Study on Requirements: Tokairo, Part Introduction The System Background Information The Companies Involved in the Project The Software House: Tokairo The Client: Tankfreight The First Installation: Shell Haven User Requirements Gathering The Characteristics of the Users, Tasks, and Environment How Tokairo Gathered the User Requirements Summary 134 Part 3 Design Work Reengineering and Conceptual Design Introduction Introduction to the Digital Library 140

5 2. Work Reengineering for the Digital Library Task Allocation for the Digital Library Conceptual Design Deriving Concrete Use Cases from Essential Use Cases Identifying Task Objects, Attributes, and Actions Marking Up the Concrete Use Cases to Identify Task Objects, Their Attributes, and Actions Prototyping Task Objects, Attributes, and Actions Creating the Content Diagram Summary 161 Design Guidance and Design Rationale Introduction Sources of Design Guidance User Interface Standards Style Guides Design Principles: Simplicity, Structure, Consistency, and Tolerance Simplicity Structure Tolerance Accessibility The Principles of Universal Design W3C Web Content Accessibility Guidelines Section The Limitations of Guidelines Design Rationale The Benefits of Recording Design Decisions How to Record Design Decisions Summary 186 Interaction Design Introduction The Human Action Cycle The Details of the Human Action Cycle Using the Human Action Cycle to Influence the Design Process Communicating the Designer's Understanding of the System Designer's Model System Image How the User Interface Enables the User to Develop an Accurate Mental Model Using Metaphors to Develop Accurate Mental Models The Benefits of Metaphor 200

6 4.2 Problems with Metaphor Choosing a Suitable Metaphor or Set of Metaphors 5. Summary XI 11 Interaction Styles Introduction Interaction Styles Command Line Menu Selection Form-Fill Direct Manipulation Anthropomorphic Blending Interaction Styles Choosing the Most Appropriate Interaction Style Summary Choosing Interaction Devices: Hardware Components Introduction Choosing Interaction Devices Interaction Devices as Tools Why Study Interaction Devices? Input Devices Keyboards, Keypads, and Buttons Pointing Devices Alternative Approaches to Entering Information Output Devices Screens Loudspeakers Simple Output Devices Alternative Approaches to Outputting Information Summary Choosing Interaction Elements: Software Components Introduction Text How to Ensure That Your Text Is Legible How to Ensure That Your Text Makes Sense Color The Characteristics of Color Choosing Colors with the Right Connotations How to Use Color Effectively Using Color to Represent Information Images Using Images Effectively Moving Images 263

7 5.1 Using Animation Effectively Using Video Clips Effectively Sound Different Types of Sound Making Good Use of Sound Effects Using Music Effectively Using Speech Effectively Problems with the Use of Sound Summary Moving from Choosing Components into Design Areas Introduction Combining Interaction Devices and Software Components Principles of Good Layout Create Natural Groupings Separate the Currently Active Components Emphasize Important Components Use White Space Effectively Make the Controls Visible Balance Aesthetics and Usability What Is a Design Area? Design Components and Design Areas Summary Case Study on Design: Tokairo, Part Introduction The Driver's Worksheet The Kiosk How Tokairo Designed the UI Establishing the Ground Rules: Simplicity and Flexibility 4.2 Choosing the Technology: Simplicity and Familiarity Developing Prototypes: Communicating Ideas Designing the Screens Designing the Worksheet Developing Prototypes: Facilitating Evaluation Two Surprises Summary Designing a Graphical User Interface (GUI) Introduction The Appearance of Widgets in Different Pieces of Software The Energetic Sports Center Domain Users Main Tasks 300

8 3.4 Environment Technology Conceptual Design Choosing Widgets to Structure the Interaction Using Primary Windows Using Secondary Windows Using Tabs Choosing Widgets to Control the Interaction Using Menus Using Tool Bars Using Command Buttons Choosing Widgets to Enter Information Using Option Buttons and Check Boxes Using List Boxes Using Text Boxes Combining GUI Widgets Summary Designing for the Web Introduction The Lovely Rooms Hotel Booking Service Domain Users Tasks Environment Technology Conceptual Design Design Principles for Web Sites High-Quality Content Often Updated Minimal Download Time Ease of Use Relevant to User's Needs Unique to the Online Medium Net-Centric Corporate Culture Designing Web Sites Designing the Web Site Structure Helping the Users Know Where They Are Helping the Users Navigate around the Site Navigation Aids Designing Home Pages and Interior Pages Designing the Home Page Designing Interior Pages Design Issues for Web Pages Widgets on Web Pages 355

9 6.2 Scrolling Designing for Different Screens and Platforms Using the Screen Area Effectively Improving the Download Time Using Style Sheets Designing for Accessibility Writing the Content of Web Pages Keep Text to a Minimum Help Users to Scan Dividing Long Blocks of Text into Separate Sections Summary The Design of Embedded Computer Systems and Small Devices Introduction Types of Embedded System Safety Critical Systems Information Appliances Design Issues for IAs Portability General Purpose versus Special Purpose Connectedness The Commercial Environment Design Guidelines for Embedded Devices UI Design Guidelines for Handheld Devices Guidelines Specific to a Manufacturer Guidelines for Kiosks Summary Case Study on Requirements, Design, and Evaluation: NATS Introduction The Final Approach Spacing Tool (FAST) National Air Traffic Services Air Traffic Management Systems Final Approach Control The FAST User Interface How the Team Developed FAST NATS Research and Development The Human Factors Unit The FAST Project Team Requirements Gathering The Domain, Users, Environment, and Usability Requirements How the Project Team Gathered the User Requirements The Design and Evaluation of the User Interface Design by Prototyping 398

10 5.2 Preparing to Evaluate Observing the Controllers Inspecting the User Interface Analyzing and Interpreting the Evaluation Data Communicating the Findings to the Customer Summary 409 Appendix 1 GUI Design Guidelines 411 Appendix 2 Principles and Guidelines for Web Site Design 413 Appendix 3 Web Sites for Users with Disabilities 417 Part 4 Evaluation Why Evaluate the Usability of User Interface Designs? Introduction Why evaluate the usability of user interface designs? Does the Interface Meet the Usability Requirements? Exploring Other Concerns in Evaluations Users, Tasks, Environment, and Domain Our Running Example: Global Warming Description of the Global Warming User Interface The Activities of Usability Evaluations The Process of Usability Evaluation Is Iterative Techniques for Usability Evaluations What Happens in a User Observation Evaluation Session? Summary Deciding on What You Need to Evaluate: The Strategy Introduction Creating an Evaluation Strategy What Is the Purpose of This Evaluation? What Type of Data Do I Want to Collect? What Am I Evaluating? What Constraints Do I Have? Documenting the Evaluation Strategy The Global Warming UI: The Evaluation Strategy DecidingWhattoTest Do You Have to Work within Any Constraints? Writing Up Your Evaluation Strategy for the Global Warming Evaluation Summary Planning who, what, When, and where Introduction Choosing Your Users 453

11 2.1 Who Is a Real User? Users Working Alone or in Pairs Number of Participants Recruiting Extra Participants Ideas for Participants Offering Incentives Recruiting Screeners and Pretest Questionnaires Choosing Users for Global Warming Creating a Timetable Decide the Duration of the Evaluation Session Create an Evaluation Timetable Preparing Task Descriptions Task Cards Task Descriptions for Global Warming Where will you do the evaluation? Field Studies Controlled Studies The Setting for the Global Warming Evaluation Arranging Usability Evaluation Sessions The Arrangements for the Global Warming Evaluation Summary Deciding How to Collect Data Introduction: Preparing to Collect Evaluation Data Timing and Logging Actions Automatic Logging of Keystrokes and Mouse Clicks Specialist Logging Software for Usability Evaluations Choosing a Logging Product Think-Aloud and Offering Help Using Cognitive Walkthrough Questions Taking Notes When Observing Users Conducting Post-Session Discussions Questionnaires Using Technologies to Help with Recording Video and Audio Recording Eye-tracking Equipment Practitioner's Choice of Technology The Global Warming Choices for Data Collection Summary Final Preparations for the Evaluation Introduction Evaluation Materials for Global Warming Roles for Evaluators 491

12 2.1 Facilitator Note-Taker Equipment Operator Observer Meeter and Greeter Recruiter The Lone Evaluator Creating an Evaluation Script An Example of an Evaluation Script Using a Script for the Global Warming Evaluation Forms to Use When asking for Permission to Record Nondisclosure Agreements The Pilot Test Participants for Your Pilot Test Design and Assemble the Test Environment Run the Pilot Test Summary Analysis and Interpretation of User Observation Evaluation Data Introduction: How to analyze and interpret data from your evaluation Collating the Data Summarizing the Data Reviewing the Data to Identify Usability Problems Working with quantitative data Working with Qualitative Data An Example of Data from Global Warming Making Decisions with Qualitative Data Interpretation of User-Observation Data Assigning Severities Recommending Changes Writing the Evaluation Report An Academic Report on Global Warming Should You Describe Your Method? Describing Your Results Summary Inspections of the User Interface Introduction Creating the Evaluation Plan for Heuristic Inspection Choosing the Heuristics The Inspectors Conducting a Heuristic Inspection Task Descriptions The Location of the Evaluation Session Collecting Evaluation Data 530

13 4. Analysis of Heuristic Inspection Data Interpretation of Heuristic Inspection Data Benefits and Limitations of Heuristic Evaluations Variations of Usability Inspection Participatory Heuristic Evaluations Guideline Reviews Standards Inspections Cognitive Walkthrough Peer Reviews Summary Variations and More Comprehensive Evaluations Introduction A Comparison of User Observation and Heuristic Inspection Observe, Listen, Compare, Measure: The Elements of Evaluation Combining the Elements for Evaluation Varying Other Aspects of the Evaluation Variations of User Observations Remote Moderated Testing Performance Measurement Evaluations Obtaining Opinions and Ideas Focus Groups Card Sorting Evaluations without People Accessibility Checkers and HTML Validators Usability Checkers Hybrid Methods Different Purposes of Evaluations Exploratory Evaluations Validation Evaluation Assessment Evaluation Comparison Evaluation Undertaking More Comprehensive Evaluations Summary 556 Part 5 Persuasion Communicating and Using Findings Introduction Making Use of Your Findings Using Your Results Communicating the Results Who Is Affected by the Changes? Who Is Involved in Your Project? 572

14 3.2 Choosing Ways to Communicate the Results Is Your Organization User Centered? Summary Winning and Maintaining Support for User-Centered Design Introduction "Skepticism" Arguments: Finding Out about Usability Organizational Goals That May Conflict with Usability "Skepticism" Arguments: Creating Curiosity Start Small Find a Champion Be an Objective Voice "Curiosity" Arguments: Moving toward Acceptance Cost of Staff Time and Accuracy Performance Measurement: Computer Time Costs of Learning and Training Continuing Support Costs Cost of Support Cost of Maintenance and Change Cost Justification Is Not the Whole Story "Acceptance" Arguments: Maintaining Momentum Be Sensitive to the Stage of the Project Balance Delivery and Usability Manage User Expectations Do Not Become Stuck on One Technique "Partnership": The Benefits Summary Summary 603 Glossary 605 References 631 Index 641