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Human Computer Interaction And Usability Discussion

Human Computer Interaction And Usability Discussion

Human Computer Interaction And Usability Discussion


beyond human-computer interaction



Color Plate 1

Figure 1.2 Novel forms of interactive products embedded with computational power (clockwise from top left):

(i) Electrolux screen- fridge that provides a range of functionality, in- cluding food manage- ment where recipes are displayed, based on the food stored in t h e fridge.

(iii) ‘geek chic’, a Levi jacket equipped with a fully integrated computer network (body area network), enabling the wearer to be fully connected to the web.


[IV) Barney, an interactive cuddly toy that makes learning enjoyable.

Figure 1.1 1 2D and 3D buttons. Which a r e easier t o distin- guish between?



Color Plate 2

Figure 2.1 An example of augmented reality. Virtual and physical worlds have been combined so that a digital image of the brain is superimposed on the person’s head, providing a new form of medical visualization.

Figure 2.14 The i-room project at Stanford: a graphical rendering of the Interactive Room Terry Winograd’s group is researching, which is an innovative technology- rich prototype workspace, integrating a variety of dis- plays and devices. An overarching aim is to explore new possibilities for people to work together (see http://graphics.stanford.EDU/projects/iwork/).

– . –

I.. , .



Color Plate 3

Figure 2.6 Recent direct-manipulation virtual environments

(a) Virtue (Daniel Reid, 1999, www-pablo.cs.uiuc.edulPro- jectNRNirtue) enables software developers to directly ma- nipulate software components and their behavior.

(b), (c) Crayoland (Dave Pape, www.ncsa.uiuc.eduNis/) is an interactive virtual environment where the child in the image on the right uses a joystick to navigate through the space. The child is interacting with an avatar in the flower world.



Color Plate 4

Figure 3.7 Dynalinking used in the PondWorld software. In the background is a simulation of a pond ecosystem, comprising perch, stickleback, beetles, tadpoles, and weeds. In the foreground is a food web diagram representing the same ecosystem but at a more abstract level. The two are dynalinked: changes made to one representation are reflected in the other. H e r e the user has clicked o n the arrow between the tadpole and the weed rep- resented in the diagram. This is shown in the PondWorld simulation as the tadpole eating the weed. The dynalinking is accompanied by a narrative explaining what is happening and sounds of dying organisms.

Figure 3.9 A see-through handset-transparency does not mean simply showing the insides of a machine but involves providing a good system image.



Color Plate 5

Figure 4.1 ‘l’he rooftop gar- den in BowieWorld, a collab- orative virtual environment (CVE) supported by The User takes part by “dressing up” as an avatar. There are hundreds of avatars to choose from, in- cluding penguins and real people. Once avatars have entered a world, they can ex- plore it and chat with other avatars.



Color Plate 6

Figure 5.3 Examples of aesthetically pleasing interactive products: iMac, Nokia cell phone and IDEO’s digital radio for the BBC.

1 Figure 5.9 Virtual screen characters:

(a) Aibo, the interactive dog.



Color Plate 7

Figure 5.1 1 I-lerman the bug watches as a stu- dent chooses roots for a plant in a n Alpinc meadow.

Figure 5.1 2 The Woggles inter- face, with icons and slider bars repl-escnting emotions. specch and actions.



Color Plate 8

Figure 5.13 Rea the real estate agent welcoming the user to look at a condo.

Figure 7.3(b) The KordGrip being used underwater

Figure 15.8 The first foam mod- els of a mobile communicator for children.




beyond human-computer interaction

John Wiley & Sons, Inc.



ACQUISITIONS EDITOR Gaynor Redvers-MuttonlPaul Crockett MARKETING MANAGER Katherine Hepburn SENIOR PRODUCTION EDITOR Ken Santor COVER DESIGNER Madelyn Lesure ILLUSTRATION EDITOR Anna Melhorn ILLUSTRATIONS Tech-Graphics, Inc. COVER IMAGE “Thoughts in Passage 11” by Michael Jon March.

Courtesy of Grand Image Publishing

This book was set in 10112 Times Ten by UG I GGS Information Services, Inc., and printed and bound by R. R. DonnelleylCrawfordsville. The cover and the color insert were printed by Phoenix Color Corporation.

This book is printed on acid free paper. m

Copyright O 2002 John Wiley & Sons, Inc. All rights reserved.

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (508) 750-8400, fax (508) 750-4470. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue, New York, NY 10158-0012, (212) 850-6011, fax (212) 850-6008, E-Mail: PERMREQ@WILEY.COM. To order books or for customer service please call 1(800)225-5945.

Library of Congress Cataloging in Publication Data. Preece, Jennifer.

Interaction design : beyond human- computer interaction1 Jennifer Preece, Yvonne Rogers, Helen Sharp.

p. cm. Includes bibliographical references and index. ISBN 0-471-49278-7 (paper : alk. paper) 1. Human-computer interaction. I. Rogers, Yvonne. 11. Sharp, Helen. 111. Title.

QA76.9.H85 P72 2002 004′.01’94c21

Printed in the United States of America 2001006730




Welcome to Interaction Design: Beyond Human-Computer Interaction, and our in- teractive website at

This textbook is for undergraduate and masters students from a range of back- grounds studying classes in human-computer interaction, interaction design, web design, etc. A broad range of professionals and technology users will also find this book useful, and so will graduate students who are moving into this area from re- lated disciplines.

Our book is called Interaction Design: Beyond Human-Computer Interaction because it is concerned with a broader scope of issues, topics, and paradigms than has traditionally been the scope of human-computer interaction (HCI). This reflects the exciting times we are living in, when there has never been a greater need for in- teraction designers and usability engineers to develop current and next-generation interactive technologies. To be successful they will need a mixed set of skills from psychology, human-computer interaction, web design, computer science, informa- tion systems, marketing, entertainment, and business.

What exactly do we mean by interaction design? In essence, we define interac- tion design as:

“designing interactive products to support people in their everyday and working lives”.

This entails creating user experiences that enhance and extend the way people work, communicate, and interact. Now that it is widely accepted that HCI has moved beyond designing computer systems for one user sitting in front of one ma- chine to embrace new paradigms, we, likewise, have covered a wider range of is- sues. These include ubiquitous computing and pervasive computing that make use of wireless and collaborative technologies. We also have tried to make the book up-to-date with many examples from contemporary research.

The book has 15 chapters and includes discussion of how cognitive, social, and affective issues apply to interaction design. A central theme is that design and eval- uation are interleaving, highly iterative processes, with some roots in theory but which rely strongly on good practice to create usable products. The book has a ‘hands-on’ orientation and explains how to carry out a variety of techniques. It also has a strong pedagogical design and includes many activities (with detailed com- ments), assignments, and the special pedagogic features discussed below.

The style of writing is intended to be accessible to students, as well as profes- sionals and general readers, so it is conversational and includes anecdotes, car- toons, and case studies. Many of the examples are intended to relate to readers’ own experiences. The book and the associated website encourage readers to be ac- tive when reading and to think about seminal issues. For example, one feature we have included in the book is the “dilemma,” where a controversial topic is aired. The aim is for readers to understand that much of interaction design needs consid-



vi Preface

eration of the issues, and that they need to learn to weigh-up the pros and cons and be prepared to make trade-offs. We particularly want readers to realize that there is rarely a right or wrong answer although there are good designs and poor designs.

This book is accompanied by a website, which provides a variety of resources and interactivities, The website offers a place where readers can learn how to design websites and other kinds of multimedia interfaces. Rather than just provide a list of guidelines and design principles, we have developed various interactivities, includ- ing online tutorials and step-by-step exercises, intended to support learning by doing.

Special features

We use both the textbook and the web to teach about interaction design. To pro- mote good pedagogical practice we include the following features:

Chapter design

Each chapter is designed to motivate and support learning:

Aims are provided so that readers develop an accurate model of what to ex- pect in the chapter.

Key points at the end of the chapter summarize what is important. Activities are included throughout the book and are considered an essential ingredient for learning. They encourage readers to extend and apply their knowledge. Comments are offered directly after the activities, because peda- gogic research suggests that turning to the back of the text annoys readers and discourages learning.

An assignment is provided at the end of each chapter. This can be set as a group or individual project. The aim is for students to put into practice and consolidate knowledge and skills either from the chapter that they have just studied or from several chapters. Some of the assignments build on each other and involve developing and evaluating designs or actual products. Hints and guidance are provided on the website. Boxes provide additional and highlighted information for readers to reflect upon in more depth.

Dilemmas offer honest and thought-provoking coverage of controversial or problematic issues. Further reading suggestions are provided at the end of each chapter. These refer to seminal work in the field, interesting additional material, or work that has been heavily drawn upon in the text. Interviews with nine practitioners and visionaries in the field enable readers to gain a personal perspective of the interviewees’ work, their philosophies, their ideas about what is important, and their contributions to the field.

Cartoons are included to make the book enjoyable.



How to use this book vii website

The aim of the website is to provide you with an opportunity to learn about inter- action design in ways that go “beyond the book.” Additional in-depth material, hands-on interactivities, a student’s corner and informal tutorials will be provided. Specific features planned include:

Hands-on interactivities, including designing a questionnaire, customizing a set of heuristics, doing a usability analysis on ‘real’ data, and interactive tools to support physical design.

Recent case studies. Student’s corner where you will be able to send in your designs, thoughts, written articles which, if suitable, will be posted on the site at specified times during the year.

Hints and guidance on the assignments outlined in the book.

Suggestions for additional material to be used in seminars, lab classes, and lectures. Key terms and concepts (with links to where to find out more about them).

Readership This book will be useful to a wide range of readers with different needs and aspirations.

Students from Computer Science, Software Engineering, Information Systems, Psychology, Sociology, and related disciplines studying courses in Interaction De- sign and Human-Computer Interaction will learn the knowledge, skills, and tech- niques for designing and evaluating state-of-the-art products, and websites, as well as traditional computer systems.

W e b and Interaction Designers, and Usability Professionals will find plenty to satisfy their need for immediate answers to problems as well as for building skills to satisfy the demands of today’s fast moving technical market.

Users, who want to understand why certain products can be used with ease while others are unpredictable and frustrating, will take pleasure in discovering that there is a discipline with practices that produce usable systems.

Researchers and developers who are interested in exploiting the potential of the web, wireless, and collaborative technologies will find that, as well as offering guid- ance, techniques, and much food for thought, a special effort has been made to in- clude examples of state-of-the-art systems.

In the next section we recommend various routes through the text for different kinds of readers.

How to use this book Interaction Design is not a linear design process but is essentially iterative and some readers and experienced instructors will want tb find their own way through the chapters. Others, and particularly those with less experience, may prefer to



viii Preface

work through chapter by chapter. Readers will also have different needs. For ex- ample, students in Psychology will come with different background knowledge and needs from those in Computer Science. Similarly, professionals wanting to learn the fundamentals in a one-week course have different needs. This book and the website are designed for using in various ways. The following suggestions are pro- vided to help you decide which way is best for you.

From beginning to end

There are fifteen chapters so students can study one chapter per week during a fifteen-week semester course. Chapter 15 contains design and evaluation case studies. Our intention is that these case studies help to draw together the contents of the rest of the book by showing how design and evaluation are done in the real world. However, some readers may prefer to dip into them along the way.

Getting a quick overview

For those who want to get a quick overview or just the essence of the book, we suggest you read Chapters 1, 6, and 10. These chapters are recommended for everyone.

Suggestions for computer science students

In addition to reading Chapters 1,6, and 10, Chapters 7 and 8 contain the material that will feel most familiar to any students who have been introduced to software development. These chapters cover the process of interaction design and the activi- ties it involves, including establishing requirements, conceptual design, and physi- cal design. The book itself does not include any coding exercises, but the website will provide tools and widgets with which to interact.

For those following the ACM-IEEE Curriculum (2001)*, you will find that this text and website cover most of this curriculum. The topics listed under each of the following headings are discussed in the chapters shown:

HC1 Foundations of Human-Computer Interaction (Chapters 1-5, 14, website).

HC2 Building a simple graphical user interface (Chapters 1 , 6 , 8 , 1 0 and the website).

HC3 Human-Centered Software Evaluation (Chapters 1,10-15, website). HC4 Human-Centered Software Design (Chapters 1,6-9,15). HC5 Graphical User-Interface Design (Chapters 2 and 8 and the website. Many relevant examples are discussed in Chapters 1-5 integrated with dis- cussion of cognitive and social issues).

*ACM-IEEE Curriculum (2001) [] is under development at the time of writing this book.




How to use this book ix

HC6 Graphical User-Interface Programming (touched upon only in Chap- ters 7-9 and on the website). HC7 HCI Aspects of Multimedia Information Systems and the web (inte- grated into the discussion of Chapters 1-5, and in examples throughout the text, and on the website). HC8 HCI Aspects of Group Collaboration and Communication Technology (discussed in 1-5, particularly in Chapter 4. Chapters 6-15 discuss design and evaluation and some examples cover these systems, as does the website.)

Suggestions for information systems students

Information systems students will benefit from reading the whole text, but instructors may want to find additional examples of their own to illustrate how issues apply to business applications. Some students may be tempted to skip Chapters 3-5 but we rec- ommend that they should read these chapters since they provide important founda- tional material. This book does not cover how to develop business cases or marketing.

Suggestions for psychology and cognitive science students

Chapters 3-5 cover how theory and research findings have been applied to interac- tion design. They discuss the relevant issues and provide a wide range of studies and systems that have been informed by cognitive, social, and affective issues. Chapters 1 and 2 also cover important conceptual knowledge, necessary for having a good grounding in interaction design.

Practitioner and short course route

Many people want the equivalent of a short intensive 2-5 day course. The best route for them is to read Chapters 1,6,10 and 11 and dip into the rest of the book for reference. For those who want practical skills, we recommend Chapter 8.

Plan your own path

For people who do not want to follow the “beginning-to-end” approach or the sug- gestions above, there are many ways to use the text. Chapters 1,6,10 and 11 provide a good overview of the topic. Chapter 1 is an introduction to key issues in the disci- pline and Chapters 6 and 10 offer introductions to design and evaluation. Then go to Chapters 2-5 for user issues, then on to the other design chapters, 2-9, dipping into the evaluation chapters 10-14 and the case studies in 15. Another approach is to start with one or two of the evaluation chapters after first reading Chapters 1, 6, 10 and 11, then move into the design section, drawing on Chapters 2-5 as necessary.

Web designer route

Web designers who have a background in technology and want to learn how to de- sign usable and effective websites are advised to read Chapters 1, 7, 8, 13 and 14.



x Preface

These chapters cover key issues that are important when designing and evaluating the usability of websites. A worked assignment runs through these chapters.

Usability professionals’ route

Usability professionals who want to extend their knowledge of evaluation techniques and read about the social and psychological issues that underpin design of the web, wireless, and collaborative systems are advised to read Chapter 1 for an overview, then select from Chapters 10-14 on usability testing. Chapters 3,4, and 5 provide dis- cussion of seminal user issues (cognitive, social, and affective aspects). There is new material throughout the rest of the book, which will also be of interest for dipping into as needed. This group may also be particularly interested in Chapter 8 which, to- gether with material on the book website, provides practical design examples.


Many people have helped to make this book a reality. We have benefited from the advice and support of our many professional colleagues across the world, our stu- dents, friends, and families and we thank you all. We also warmly thank the following people for reviewing the manuscript and making many helpful suggestions for im- provements: Liam Bannon, Sara Bly, Penny Collings, Paul Dourish, Jean Gasen, Peter Gregor, Stella Mills, Rory O’Connor, Scott Toolson, Terry Winograd, Richard Furuta, Robert J.K. Jacob, Blair Nonnecke, William Buxton, Carol Traynor, Blaise Liffich, Jan Scott, Sten Hendrickson, Ping Zhang, Lyndsay Marshall, Gary Perlman, Andrew Dillon, Michael Harrison, Mark Crenshaw, Laurie Dingers, David Carr, Steve Howard, David Squires, George Weir, Marilyn Tremaine, Bob Fields, Frances Slack, Ian Graham, Alan O’Callaghan, Sylvia Wilbur, and several anonymous re- viewers. We also thank Geraldine Fitzpatrick, Tim and Dirk from DSTC (Australia) for their feedback on Chapters 1 and 4, Mike Scaife, Harry Brignull, Matt Davies, the HCCS Masters students at Sussex University (2000-2001), Stephanie Wilson and the students from the School of Informatics at City University and Information Systems Department at UMBC for their comments.

We are particularly grateful to Sara Bly, Karen Holtzblatt, Jakob Nielsen, Abi- gail Sellen, Suzanne Robertson, Gitta Salomon, Ben Shneiderman, Gillian Cramp- ton Smith, and Terry Winograd for generously contributing in-depth interviews.

Lili Cheng and her colleagues allowed us to use the Hutchworld case study. Bill Killam provided the TRZS case study. Keith Cogdill supplied the MEDLZNE- plus case study. We thank Lili, Bill, and Keith for supplying the basic reports and commenting on various drafts. Jon Lazar and Dorine Andrews contributed mater- ial for the section on questionnaires, which we thank them for.

We are grateful to our Editors Paul Crockett and Gaynor Redvers-Mutton and the production team at Wiley: Maddy Lesure, Susannah Barr, Anna Melhorn, Gemma Quilter, and Ken Santor. Without their help and skill this book would not have been produced. Bill Zobrist and Simon Plumtree played a significant role in persuading us to work with Wiley and we thank them too.



About the authors xi

I About the authors The authors are all senior academics with a background in teaching, researching, and consulting in the UK, USA, Canada, Australia, and Europe. Having worked together on two other successful text books, they bring considerable experience in curriculum development, using a variety of media for distance learning as well as face-to-face teaching. They have considerable knowledge of creating learning texts and websites that motivate and support learning for a range of students.

All three authors are specialists in interaction design and human-computer in- teraction (HCI). In addition they bring skills from other discipline~. Yvonne Rogers is a cognitive scientist, Helen Sharp is a software engineer, and Jenny Preece works in information systems. Their complementary knowledge and skills enable them to cover the breadth of concepts in interaction design and HCI to pro- duce an interdisciplinary text and website. They have collaborated closely, sup- porting and commenting upon each other’s work to produce a high degree of integration of ideas with one voice. They have shared everything from initial con- cepts, through writing, design and production.




Con tents

Chapter 1 What is interaction design? 1 1 . I Introduction 1 1.2 Good and poor design 2

1.2.1 What to design 4 1.3 What is interaction design? 6

1.3.1 The makeup of interaction design 6 1.3.2 Working together as a multidisciplinary team 9 1.3.3 Interaction design in business 10

1.4 What is involved in the process of interaction design? 12 1.5 The goals of interaction design 13

1.5.1 Usability goals 1 A 1.5.2 User experience goals 18

1.6 More on usability: design and usability principles 20 1.6.1 Heuristics and usability principles 26

Interview with Gitta Salomon 3 1

Chapter 2 Understanding and concep~alizing interaction 35 2.1 lntroduction 35 2.2 Understanding the problem space 36 2.3 Conceptual models 39

2.3.1 Conceptual models based on activities 41 2.3.2 Conceptual models based on objects 51 2.3.3 A case of mix and match? 54

2.4 Interface metaphors 55 2.5 Interaction paradigms 60 2.6 From conceptual models to physical design 64

Interview with Terry Winograd 70

Chapter 3 Understanding users 73 3.1 Introduction 73 3.2 What i s cognition? 74 3.3 Applying knowledge from the physical world to the digital world 90 3.4 Conceptual frameworks for cognition 92

3.4.1 Mental models 92



xiv Contents

3.4.2 Information processing 96 3.4.3 External cognition 98

3.5 Informing design: from theory to practice 101

Chapter 4 Designing for collaboration and communica~ion 105 4.1 Introduction 105 4.2 Social mechanisms used in communication and collaboration 106

4.2.1 Conversational mechanisms 107 4.2.2 Designing collaborative technologies to support conversation

110 4.2.3 Coordination mechanisms 1 18 4.2.4 Designing collaborative technologies to support coordination

122 4.2.5 Awareness mechanisms 124 4.2.6 Designing collaborative technologies to support awareness 126

4.3 Ethnographic studies of collaboration and communication 129 4.4 Conceptual frameworks 130

4.4.1 The language/action framework 130 4.4.2 Distributed cognition 133

Interview with Abigail Sellen 138

Chapter 5 Understanding how interfaces affect users 141 5.1 lntroduction 141 5.2 What are affective aspects? 142 5.3 Expressive interfaces 143 5.4 User frustration 147

5.4.1 Dealing with user frustration 152 5.5 A debate: the application of anthropomorphism to interaction design 153 5.6 Virtual characters: agents 157

5.6.1 Kinds of agents 1 57 5.6.2 General design concerns 160

Chapter 6 The process of interaction design 165 6.1 Introduction 165 6.2 What i s interaction design about? 166

6.2.1 Four basic activities of interaction design 1 68 6.2.2 Three key characteristics of the interaction design process 170

6.3 Some practical issues 170 6.3.1 Who are the users? 171



Contents xv

Chapter 7

1 Chapter 8

6.3.2 What do we mean by “needs”? 172 6.3.3 How do you generate alternative designs? 174 6.3.4 How do you choose among alternative designs? 179

6.4 Lifecycle models: showing how the activities are related I 82 6.4.1 A simple lifecycle model for interaction design 186 6.4.2 Lifecycle models in software engineering 187 6.4.3 Lifecycle models in HCI 192

Interview with Gillian Crampton Smith 198

Identifying needs and establishing requirements 201 7.1 Introduction 201 7.2 What, how, and why? 202

7.2.1 What are we trying to achieve in this design activity? 202 7.2.2 How can we achieve this? 202 7.2.3 Why bother? The importance of getting it right 203 7.2.4 Why establish requirements? 204

7.3 What are requirements? 204 7.3.1 Different kinds of requirements 205

7.4 Data gathering 21 0 7.4.1 Data-gathering techniques 21 1 7.4.2 Choosing between techniques 21 5 7.4.3 Some basic datmgathering guidelines 21 6

7.5 Data interpretation and analysis 21 9 7.6 Task description 222

7.6.1 Scenarios 223 7.6.2 Use cases 226 7.6.3 Essential use cases 229

7.7 Task analysis 231 7.7.1 Hierarchical Task Analysis (HTA) 231

Interview with Suzanne Robertson 236

Design, prototyping and construction 239 8.1 lntroduction 239 8.2 Prototyping and construction 240

8.2.1 What is a prototype? 240 8.2.2 Why prototype? 241 8.2.3 Low-fidelity prototyping 243 8.2.4 High-fidelity prototyping 245 8.2.5 Compromises in prototyping 246



xvi Contents

8.2.6 Construction: from design to implementation 248 8.3 Conceptual design: moving from requirements to first design 249

8.3.1 Three perspectives for developing a conceptual model 250 8.3.2 Expanding the conceptual model 257 8.3.3 Using scenarios in conceptual design 259 8.3.4 Using prototypes in conceptual design 262

8.4 Physical design: getting concrete 264 8.4.1 Guidelines for physical design 266 8.4.2 Different kinds of widget 268

8.5 Tool support 275

Chapter 9 User-centered approaches to interaction design 279 9.1 Introduction 279 9.2 Why i s it important to involve users at all? 280

9.2.1 Degrees of involvement 281 9.3 What i s a user-centered approach? 285 9.4 Understanding users’ work: applying ethnography in design 288

9.4.1 Coherence 293 9.4.2 Contextual Design 295

9.5 involving users in design: Participatory Design 306 9.5.1 PICTIVE 307 9.5.2 CARD 309

Interview with Karen Holtzblatt 31 3

Chapter 1 0 Introducing evaluation 31 7 1 0.1 Introduction 31 7 10.2 What, why, and when to evaluate 31 8

10.2.1 What to evaluate 31 8 10.2.2 Why you need to evaluate 31 9 10.2.3 When to evaluate 323

10.3 Hutchworld case study 324 1 0.3.1 How the team got started: early design ideas 324 10.3.2 How was the testing done? 327 10.3.3 Was it tested again? 333 10.3.4 Looking to the future 334

10.4 Discussion 336

Chapter 1 1 An evaluation framework 339 1 1 .1 Introduction 339



Contents xvii

1 1.2 Evaluation paradigms and techniques 340 1 1.2.1 Evaluation paradigms 341 1 1.2.2 Techniques 345

1 1.3 D E C I D E: A framework to guide evaluation 348 1 1.3.1 Determine the goals 348 1 1.3.2 Explore the questions 349 1 1.3.3 Choose the evaluation paradigm and techniques 349 1 1.3.4 identify the practical issues 350 1 1.3.5 Decide how to deal with the ethical issues 351 1 1.3.6 Evaluate, interpret, and present the data 355

1 1.4 pilot studies 356

Chapter 12 Observing users 359 1 2.1 Introduction 359 12.2 Goals, questions and paradigms 360

12.2.1 What and when to observe 361 1 2.2.2 Approaches to observation 363

1 2.3 How to observe 364 12.3.1 In controlled environments 365 1 2.3.2 In the field 368 12.3.3 Participant observation and ethnography 370

12.4 Data collection 373 12.4.1 Notes plus still camera 374 12.4.2 Audio recording plus still camera 374 12.4.3 Video 374

1 2.5 Indirect observation: tracking users’ activities 377 12.5.1 Diaries 377 12.5.2 Interaction logging 377

12.6 Analyzing, interpreting and presenting data 379 12.6.1 Qualitative analysis to tell a story 380 1 2.6.2 Qualitative analysis for categorization 381 12.6.3 Quantitative data analysis 384 12.6.4 Feeding the findings back into design 384

Interview with Sara Bb 387

Chapter 13 Asking users and experts 389 1 3.1 introduction 389 1 3.2 Aking users: interviews 390

13.2.1 Developing questions and planning an interview 390



xviii Contents

13.2.2 Unstructured interviews 392 13.2.3 Structured interviews 394 13.2.4 Semi-structured interviews 394 13.2.5 Group interviews 396 1 3.2.6 Other sources of interview-li ke feedback 397 1 3.2.7 Data analysis and interpretation 398

13.3 Asking users: Questionnaires 398 13.3.1 Designing questionnaires 398 1 3.3.2 Question and response format 400 13.3.3 Administering questionnaires 404 13.3.4 Online questionnaires 405 1 3.3.5 Analyzing questionnaire data 407

13.4 Asking experts: Inspections 407 13.4.1 Heuristic evaluation 408 1 3.4.2 Doing heuristic evaluation 41 0 1 3.4.3 Heuristic evaluation of websites 41 2 1 3.4.4 Heuristics for other devices 41 9

1 3.5 Asking experts: walkthroughs 420 I 3.5.1 Cognitive walkthroughs 420 1 3.5.2 Pluralistic walkthroughs 423

Interview with Jakob Nielsen 426

Chapter 14 Testing and modeling users 429 1 4.1 Introduction 429 14.2 User testing 430

14.2.1 Testing MEDLINE~~us 432 14.3 Doing user testing 438

14.3.1 Determine the goals and explore the questions 439 14.3.2 Choose the paradigm and techniques 439 14.3.3 Identify the practical issues: Design typical tasks 439 14.3.4 Identify the practical issues: Select typical users 440 14.3.5 Identify the practical issues: Prepare the testing

conditions 441 14.3.6 Identify the practical issues: Plan how to run the tests 442 1 4.3.7 Deal with ethical issues 443 14.3.8 Evaluate, analyze, and present the data 443

14.4 Experiments 443 14.4.1 Variables and conditions 444 14.4.2 Allocation of participants to conditions 445



Contents xix

14.4.3 Other issues 446 14.4.4 Data collection and analysis 446

1 4.5 Predictive models 448 1 4.5.1 The W M S model 449 1 4.5.2 The Keystroke level model 450 14.5.3 Benefits and limitations of W M S 453 14.5.4 Fitts’ Law 454

Interview with Ben Shneiderman 457

Chapter 15 Design and evaluation in the real world: communicators and advisory systems 461 15.1 Introduction 461 15.2 Key Issues 462 15.3 Designing mobile communicators 463

15.3.1 Background 463 15.3.2 Nokia’s approach to developing a communicator 464 15.3.3 Philip’s approach to designing a communicator for children

474 15.4 Redesigning part of a large interactive phone-based response system 482

1 5.4.1 Background 483 15.4.2 The redesign 483

Reflections from the Authors 491

References 493

Credits 503

Index 509




I by Gary Perlman

As predicted by many visionaries, devices everywhere are getting “smarter.” My camera has a multi-modal hierarchical menu and form interface. Even my toaster has a microprocessor. Computing is not just for computers anymore. So when the authors wrote the subtitle “beyond human-computer interaction,” they wanted to convey that the book generalizes the human side to people, both individuals and groups, and the computer side to desktop computers, handheld computers, phones, cameras . . . maybe even toasters.

My own interest in this book is motivated by having been a software developer for 20 years, during which time I was a professor and consultant for 12. Would the book serve as a textbook for students? Would it help bring software development practice into a new age of human-centered interaction design?

A textbook for students . . . More than anything, I think students need to be motivated, inspired, challenged, and I think this book, particularly Chapters 1-5, will do that. Many students will not have the motivating experience of seeing projects and products fail because of a lack of attention, understanding, and zeal for the user, but as I read the opening chapters, I imagined students thinking, “This is what I’ve been looking for!” The in- terviews will provide students with the wisdom of well-chosen experts: what’s im- portant, what worked (or didn’t), and why. I see students making career choices based on this motivating material.

The rest of the book covers the art and some of the science of interaction de- sign, the basic knowledge needed by practitioners and future innovators. Chapters 6-9 give a current view of analysis, design, and prototyping, and the book’s website should add motivating examples. Chapters 10-14 cover evaluation in enough depth to facilitate understanding, not just rote application. Chapter 15 brings it all to- gether, adding more depth. For each topic, there are ample pointers to further reading, which is important because interaction design is not a one-book discipline.

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