DESIGNING THE USER INTERFACE ,., o C -::0 f ::c m o f o Z CJ) -! ::0 » -! rT1 Ci) Congratulations! .: : Thankyoufor pUfchasinga.nevvcopyotOesigning the User Interface, Fourth Edition. Your textbook includes six month$ of prepaid access to the book's Companion Website. This prepaid sUbscription provides yoU with fullaccessto all reader resourCes,including: Links to hundreds of HCI reso urces, examples, and research, which enhance and expand upon the material in each chapter. lIII Self-assessment questions. IiIi Assignments and projects. Ill! And more! To access the Designing the User Interface Companion Website for the first time: You will need to register online using a computer with an Internet connection and a Web browser. The process takes just a couple of minutes and only needs to be completed once. 1. Go to http://www.aw-bc.com/dtui. 2. Click General Resources. 3. Click the Register button. 4. 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H DESIGNING THE USER INTERFACE DESIGNING THE USER INTERFACE University of Maryland, College Park Boston San Francisco New York London Toronto Sydney Tokyo Singapore Madrid Mexico City Munich Paris Cape Town Hong Kong Montreal .,., o c :::c -I :::c m Cl -I o Z en -I ':1J ::; m GJ m en .,., o ':1J m .,., .,., m CJ -l < m :r: c :s: » z I CJ o :s: -0 C -l m ':1J Z -l m ':1J » CJ ::! o z Executive Editor Senior Acquisitions Editor Project Editor Marketing Manager Senior Marketing Coordinator Senior Production Supervisor Project Management Copyeditor Proofreader Indexer Composition and Art Cover and Interior Designer Cover Photos Prepress and Manufacturing Susan Hartman Sullivan Michael Hirsch Maite Suarez-Rivas Nathan Schultz Lesly Hershman Jeffrey Holcomb Edalin Michael, Argosy Publishing Rachel Wheeler Kim Cofer Larry Sweazy Argosy Publishing Joyce Cosentino Wells © 2004 Getty Images Caroline Fell Access the latest information about Addison-Wesley titles from our World Wide Web site: http://www.aw-bc.com/computing Many ofthe designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and Addison- Wesley was aware ofa trademark claim, the designations have been printed in initial caps or all caps. The programs and applications presented in this book have been included for their instruc- tional value. They have been tested with care, but are not guaranteed for any particular purpose. The publisher does not offer any warranties or representations, nor does it accept any liabilities with respect to the programs or applications. Library of Congress Cataloging-in-Publication Data Shneiderman, Ben. Designing the user interface: strategies for effective human-computer interaction / Ben Shneiderman, Catherine Plaisant 4th ed. p.cm. Includes bibliographical references and index. ISBN 0-321-19786-0 1. Human-computerinteraction. 2. User interfaces (Computer systems) I. Plaisant, Catherine. II. Title. QA76.9.H85S542004 005.1 dc22 2003068940 Copyright ©2005 by Pearson Education, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval sys- tem, o~ transmitted, ~n any. form orbyany means, electronic, mechanical, photocopying, recordmg, or otherwise, wIthout the prior written permission of the publisher. Printed in the United States of America. ISBN 0-321-19786-0 1 2 3 4 5 6 78 9 1O-QWT-08 07 06 05 To Jenny and Peter; Anna, Sara, and Thomas Preface Designing the User Interface is written for students, researchers, designers, man- agers, and evaluators of interactive systems. It presents a broad survey of how to develop high-quality user interfaces for interactive systems. Readers with backgrounds in computer science, psychology, industrial engineering, informa- tion science, information systems, business, education, and communications should all find fresh and valuable material. Our goals are to encourage greater attention to usability issues and to promote further scientific study of human- computer interaction. Since publication of the first three editions ofthis book in 1986,1992, and 1998, practitioners and researchers have grown more numerous and influential. The quality of interfaces has improved greatly, but the community of users and their diversity has grown dramatically. Researchers and designers could claim suc- cess, but user expectations are higher, applications are more demanding, and the variety of platforms has grown. In addition to desktop computers, designers must now accommodate web-based services and mobile devices. At the same time, some innovators provoke us with virtual and augmented realities, whereas others offer alluringscenarios for ubiquitous computing, embedded devices, and tangible user interfaces. These innovations are important, but much work remains to improve the experiences of novice and expert users who still struggle with too many frustra- tions. These problems must be resolved if we are to achieve the goal of universal usability, enabling all citizens in every country to enjoy the benefits of these new technologies. This book is meant to inspire students, guide designers, and pro- voke researchers. Keeping up with the innovations in human-computer interactionis a demand- ing task. Requests for an update to the third edition began shortly after its publi- cation. The growth of the field has encouraged me (Ben Shneiderman), the author of the first three editions, to work with a co-author (Catherine Plaisant), who has been a long-time valued research partner. We harvested information from books and journals, scanned the World Wide Web, attended conferences, and consulted with colleagues. Then we returned to our keyboards to write. Our first drafts were only a starting point to generate feedback from colleagues, practitioners, and students. The work was intense, but satisfying. We hope you will put these ideas to work and produce innovations for us to report in future editions. vii viii Preface New in the Fourth Edition Readers will see the dynamism of human-computer interaction reflected in the substantial changes to this fourth edition. The good news is that most universi- ties now offer courses in this area and some require it in computer science or otherdisciplines. There is still some resistance, but courses and degree programs in human-computer interaction are a growing phenomenon at every level on a worldwide basis. Corporate and government commitment to usability engineer- ing grows stronger daily, although many usability practitioners must still fight to be heard. The business case for usability has been made repeatedly and whole Web sites describe scores of studies demonstrating strong return on investment for usability efforts. Comments from instructors who used the third edition were influential in our revisions. The main change was to delete the chapteron the World Wide Web and instead describe Web-based, desktop, and mobile device designs throughout. Every chapteris updated with fresh ideas, examples, figures, and references. The opening chapter addresses the growing issue of ensuring universal usability for increasingly diverse users of interactive systems. Then guidelines, principles, and theories are substantially updated to reflect new ways of thinking. Part II covers the refinements to development methodologies, evaluation techniques, and software tools. Part III presents progress in direct manipulation and its extensions such as virtual and augmented reality, as well as changes to menus, form fillin, and command languages brought about by the new platforms, espe- cially consumer electronics devices. Since collaborative interfaces have become so central, this chapteris moved forward in thebook. Part IV emphasizes Quality ofService and a series of important design issues. Since user manuals and online help are vital to serve the goal of universal usability, that chapter is thoroughly revised. Finally, information search and visualization get special coverage since we believe that these topics will continue to grow in importance. We strive to give balanced presentations on controversial topics such as 3D, speech, and natural language interfaces. Philosophical controversies such as the degree of human control and the role of animated characters are treated care- fully to present fairly the viewpoints that differ from our own. We gave col- leagues a chance to comment on these sections, and made a special effort to provide a balanced presentation while making our opinions clear. Readers will have to judge for themselves whether we succeeded. Instructors wanted more guidelines and summary tables; these elements are showninboxes throughoutthebook. ThePractitionerSummaries and Researcher Agendas remain popular; they are updated. The references are expanded and freshened with many new sources, with classic papers stilI included. Because Preface ix some of the previously cited works were difficult to find, a much larger percent- age of the references now are widely available sources. Figures, especially those showing screen designs, age quickl~ so many new userinterfaces are shown. The printing in full color makes these figures even more valuable. Ways to UseThis Book We hope that practitioners and researchers who read this book will want to keep it on their shelves to consult when they are working on a new topic or seeking pointers to the literature. Instructors may choose to assign the full text in the order that we present it or to make selections from it. The opening chapter is a good starting pointfor most students, but instructors may take different paths depending on their disci- plines. For example, instructors might emphasize the following chapters, listed by area: • Computer science: 2, 5, 6, 7,8, 9, 10, 14 • Psychology: 2, 4, 6,10,11,12,13,14 • Industrial engineering: 2, 4, 6, 10, 11, 12, 13, 14 • Library and information science: 2,4, 10, 12, 13, 14 • Business and information systems: 3, 4,6,10,11,12,14 • Education technology: 2,4,6,10, 13, 14 • Communication arts and media studies: 4, 6, 10, 12, 13 • Technical writing and graphic design: 3,4,6, 12, 13 Companion Web Site (www.aw-bc.com/DTUI) The presence of the World Wide Web has a profound effect on researchers, designers, educators, and students. We want to encourage intense use of the Web by all these groups and to integrate it into common practice. However, the volatility of the Web is not in harmony with the pennanence of printed books. Publishing Web site URLs in the book would have been risky, because changes are made daily. For these and other reasons, we have established a Companion Web site to accompany this book. We hope that every reader will visit the site and send us ideas for improving it. x Preface Supplements A variety of supplemental materials for this text are available at the book's Com- panion Web site: www.aw-bc.com/DTUI. The following are accessible to all readers who register using the prepaid access card in the front of this book: • Links to hundreds of human-computer interaction resources, examples, and research that enhance and expand on the material in each chapter • Chapter/section summaries • Self-test questions and discussion questions for each chapter • Homework assignments and projects Acknowledgments Writing is a lonely process; revising is a social one. We are grateful to the many colleagues and students who contributed their suggestions. We appreciate the strong contributions from Jean-Daniel Fekete to Chapter5 and Jennifer Preece to Chapter 10. Our close daily partners at the University of Maryland have had a great influence on our work: Ben Bederson, Allison Druin, Kent Norman, Anne Rose, and Fran<;ois Guimbretiere. We give special thanks to Charles Kreitzberg and Gary Marchionini for their personal and professional support over many years. Extensive comments from the review panel played a strong role in our revi- sions. These individuals made numerous constructive suggestions: Robert St. Amant, North Carolina State University Catherine I. Beaton, Rochester Institute of Technology Richard F. Bellaver, Ball State University William H. Bowers, Penn State Berks-Lehigh Valley College Roger J. Chapman, Ohio State University AndrewJohnson, University of Illinois at Chicago Bill Killam, User-Centered Design, Inc. Alfred Kobsa, University of California, Irvine Adrienne Olnick Kutzschan, Queen's University, Canada Bruce R. Maxim, University of Michigan-Dearborn D. Scott McCrickard, Virginia Tech Jane Webster, Queen's University, Canada [...]... success in the public reading rooms The next step in evolution was the development of a World Wide Web version of the catalog to allow users anywhere in the world to access the catalog and other databases These changing user communities and requirements each led to interface revisions, even though the database and services remained similar Careful determination of the user community and of the benchmark... gUidelines They have a thorough understanding of the diverse community of users and the tasks that must be accomplished Moreover, they are deeply committed to serving the users, which strengthens their resolve when they face the pressures of short deadlines, tight budgets, and weak-willed compromisers Effective interfaces generate positive feelings of success, competence, mastery, and clarity in the user. .. payments User interfaces are also controversial because of their central role in national identification schemes, homeland defense, crime fighting, medical records management, and so on In the aftermath of the September 11, 2001 terrorist attacks, some members of the U.s Congress blamed the inadequacies of user interfaces for the failure to detect the terrorists At an individual level, user interfaces... "metallic" theme The top-left window shows eBay (http://www.ebay.com) a popular online auction site The top-right window shows an Xterm window, which gives users direct access into the Unix underpinnings of Mac X ITunes, the built-in music player for Mac, is shown on the bottom left The bottom-right program is iCal, the built-in calendar program The bottom of the screen also shows the Dock, the menu... testing The user manuals and the online help can be written before the implementation to provide another review and perspective on the design Next, the implementation can be carried out with proper sofhvare tools; this task should be a modest one if the design is complete and precise Finally, the acceptance test certifies that the delivered interface meets 1.4 Usability Motivations the goals of the designers... among systems These functional purposes are good starting points, but effective interfaces might also enhance the quality of life for users or improve their communities 1.2 Usability Requirements Setting such goals is controversial, and the goals vary across cultures These broader issues are left for the Afterword The first goal in requirements analysis (see Box 1.1) is to ascertain the users/ needs-that... manager The top-left window is GNU Emacs, an editing environment popular for programming At the bottom left is a terminal window which provides a simple command-line interface for the user The top-right window isThe GIMP, a graphical image manipulation program; below this is the Mozilla browser, displaying Slashdot.org, a popular news web site At the very bottom is XMMS, for playing music The taskbar at the. .. in the user community The users are not encumbered by the interface and can predict what will happen in response to each of their actions When an interactive system is well designed, the interface almost disappears, enabling users to concentrate on their work, exploration, or pleasure Creating an environment in which tasks are carried out almost effortlessly and users are "in the flow" requires a great... Gross differences between interfaces require substantial retraining and burden users in many ways Incompatible storage formats and hardware and software versions cause frustration, inefficiency, and delay Designers must decide whether the improvements they offer are useful enough to offset the disruption to the users Box 1.1 Goals for requirements analysis 1 Ascertain the users' needs 2 Ensure proper... community of users may be inappropriate for another community An efficient design for one class of tasks may be inefficient for another class The relativity of design played a central role in the evolution of information services at the u.s Library of Congress (Fig 1.7) Two of the major uses of computer systems were cataloging new books and searching the online book catalog Separate interfaces for these tasks . resourCes,including: Links to hundreds of HCI reso urces, examples, and research, which enhance and expand upon the material in each chapter. lIII Self-assessment questions. IiIi Assignments and projects. Ill! And more! To access the Designing the User Interface. this Companion Website once. After that, you can access the site by going to http://www.aw-bc.com/dtui.c1icking "General Resources," and providing your Login Name and Password when prompted. "IMPORTANT: The Access Code on this page can only be used once to establish a subscription to the Designing the User Interface, Fourth Edition Companion Website. This subscription