The UX Book Process and Guidelines for Ensuring a Quality User Experience

This book is destined to become a primary reference for just about anyone
involved in the development of inter active products of almost any kind. It
addresses both the design process and design principles and goes beyond
traditional usability to address all aspects of the user experience. The authors
have distilled two careers’ worth of research, practice and teaching into a
concise, practical and comprehensive guide for anyone involved in designing for
the user experience of interactive products.—Deborah J. Mayhew, Deborah J.
Mayhew & Associates
The UX Book covers the methods and guidelines for interaction design and
evaluation that have been shown to be the most valuable to students and
professionals. The students in my classes have been enthusiastic about the
previous versions of this text that they used. This book will benefit anyone who
wants to learn the right way to create high quality user experiences. Like good
user interfaces, this text has been refined through multiple iterations and
feedback with actual users (in this case, feedback from students and faculty who
used earlier versions of the book in classes), and this is evident in the final
result.— Brad A. Myers, Professor, Human-Computer Interaction Institute,
School of Computer Science, Carnegie Mellon University
The UX Book takes on a big challenge: a comprehensive overview of what it
takes to design great user experiences. Hartson and Pyla combine theory with
practical techniques: you leave the book knowing not just what to do, but why it’s
important.—Whitney Quesenbery, WQusability, author, Global UX: Design and
research in a connected world
Intentionally left as blank
The UX Book
Process and Guidelines for Ensuring
a Quality User Experience
Intentionally left as blank
The UX Book
Process and Guidelines for Ensuring

a Quality User Experience
REX HARTSON
PARDHA S. PYLA
AMSTERDAM • BOSTON • HEIDELBERG • LONDON
NEW YORK • OXFORD • PARIS • SAN DIEGO
SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO
Mor
g
an Kaufmann is an imprint of Elsevier
Acquiring Editor: Rachel Roumeliotis
Development Editor: David Bevans
Project Manager: Andre
´
Cuello
Designer: Joanne Blank
Cover Designer: Colin David Campbell of Bloomberg L.P.
Morgan Kaufmann is an imprint of Elsevier
225 Wyman Street, Waltham, MA 02451, USA
#
2012 Elsevier, Inc. All rights reserved.
No part of this publication may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or any information storage and
retrieval system,without permission in writing from the publisher. Details on how to seek permission,
further information about the Publisher’s permissions policies and our arrangements with
organizations such as the Copyright Clearance Center and the Copyright Licensing Agency,
can be found at our website: www.elsevier.com/permissions.
This book and the individual contributions contained in it are protected under copyright by
the Publisher (other than as may be noted herein).
Notices
Knowledge and best practice in this field are constantly changing. As new research and

experience broaden our understanding, changes in research methods or professional practices,
may become necessary. Practitioners and researchers must always rely on their own experience and
knowledge in evaluating and using any information or methods described herein. In using such
information or methods they should be mindful of their own safety and the safety of others, including
parties for whom they have a professional responsibility.
To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors,
assume any liability for any injury and/or damage to persons or property as a matter of products
liability, negligence or otherwise, or from any use or operation of any methods, products,
instructions, or ideas contained in the material herein.
Library of Congress Cataloging-in-Publication Data
Application submitted
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
ISBN: 978-0-12-385241-0
Printed in the United States of America
121314 10987654321
For information on all MK publications visit our website at www.mkp.com
“Don’t panic!”
1
1
Douglas Adams, The Hitchhiker’s Guide to the Galaxy
Intentionally left as blank
Preface
GOALS FOR THIS BOOK
Our main goal for this book is simple: to help readers learn how to create and
refine interaction designs that ensure a quality user experience (UX). A good
user interface is like an electric light: when it works, nobody notices it. (We used
to be able to use the telephone as a similar example, but now multifunction
cell phones with all kinds of modalities have thrown that example under the
bus.) A good user interface seems obvious, but what is not obvious is how to

design it so that it facilitates a good user experience. Thus, this book addresses
both what constitutes a positive user experience and the process by which it
can be ensured.
Books need to be designed too, which means establishing user (reader)
experience goals, requirements, user role (audience) definitions, and the like.
Our goals for the reader experience include ensuring that:
n the book is easy to read
n the material is easy to learn
n the material is easy to apply
n the material is useful to students and practitioners
n the reader experience is at least a little bit fun
Our goals for the book content include:
n expanding the concept of traditional usability to a broader notion of user experience
n providing a hands-on, practical guide to best practices and established principles in a
UX lifecycle
n describing a pragmatic process built on an iterative evaluation-centered UX lifecycle
template for managing the overall development effort
n expanding the traditional role of design in the iterative lifecycle to embrace design
thinking and ideation to address the new characteristics embodied within user
experience
n providing interaction design guidelines, including in-depth discussion of affordances
and other foundational concepts
n facilitating an understanding of key interaction design creation and refinement
activities, such as:
n contextual inquiry to understand user work that the design is to support
n contextual analysis to make sense of the raw contextual inquiry data
n requirements extraction
n design-informing modeling
n conceptual and detailed design
n establishing user experience goals, metrics, and targets

n building rapid prototypes
n performing formative user experience evaluation
n iterative interaction design refinement.
n describing alternative agile UX development methods
n providing pointers on how to get started with these ideas in your own
work environment
Our goals for scope of coverage include:
n depth of understanding—detailed information about different aspects of the UX
process (like having an expert accompanying the reader)
n breadth of understanding—as comprehensive as space permits
n range of application—the process and the design infrastructure and vocabulary,
including guidelines, are not just for GUIs and the Web but for all kinds of interaction
styles and devices, including ATMs, refrigerators, road signs, ubiquitous computing,
embedded computing, and everyday things.
As we were wrapping up this book, the following quote from Liam Bannon
(2011) came to our attention :
Some years ago, HCI researcher Panu Korhonen of Nokia outlined to me how HCI is
changing, as follows: In the early days the Nokia HCI people were told “Please evaluate our
user interface, and make it easy to use.” That gave way to “Please help us design this user
interface so that it is easy to use.” That, in turn, led to a request: “Please help us find what
the users really need so that we know how to design this user interface.” And now, the
engineers are pleading with us: “Look at this area of life, and find us something interesting!”
This, in a nutshell, tells a story of how HCI has moved from evaluation of interfaces through
design of systems and into general sense-making of our world.
x PREFACE
We were struck by this expressive statement of past, present, and future
directions of the field of HCI. It was our goal in this book to embrace this scope
of historical roots, the changing perspectives of thought, and future design
directions.
USABILITY IS STILL IMPORTANT

The study of usability, a key component of ensuring a quality user experience, is
still an essential part of the broad and multidisciplinary field of human–
computer interaction. It is about getting our users past the technology and
focusing on getting things done for work. In other words, it is about designing
the technology as an extension of human capabilities to accomplish something
and to be as transparent as possible in the process.
A simple example can help boost this oft-unexplained imperative, “make it
transparent,” into more than a nice platitude. Consider the simple task of
writing with pencil and paper. The writer’s focus is all about capturing
expressions to convey content and meaning. Much mental energy can be
directed toward organizing the thoug hts and finding the right word s to e xpress
them. No thought at all should be necessary toward the writing tools, the pencil
and paper, or computer-based word processor. These tools are simply an
extension of the writer. Until, that is, the occurrence of a breakdown, something
that causes an attention shift from the task to the tools.
Perhaps the pencil lead breaks or a glitch occurs in the word processor
software. The writer must turn attention away from the writing and think about
how to get the software to work, making the tool that was transparent to the
writer in the writing task become the focus of a breakdown recovery task
(Heidegger, 1962; Weller & Hartson, 1992). Similarly, interaction designs that
cause usability breakdowns for users turn attention away from the task to the
computer and the user interface.
BUT USER EXPERIENCE IS MORE THAN USABILITY
As our discipline evolves and matures, more and more technology companies
are embracing the principles of usability engineering, investing in sophisticated
usability labs and personnel to “do usability.” As these efforts are becoming
effective at ensuring a certain level of usability in the products, leveling the field
on that front, new factors have emerged to distinguish the different competing
products.
xiPREFACE

While usability is essential to making technology transparent, in these days
of extreme competition among different products and greater consumer
awareness, that is not sufficient. Thus, while usability engineering is still a
foundation for what we do in this book, it does not stop there. Because the focus
is still on designing for the human rather than focusing on technology, “user-
centered design” is still a good description. We now use a new term to express a
concern beyond just usability: “user experience.”
The concept of user experience conjures a broader image of what users come
away with, inviting comparisons with theatre (Quesenbery, 2005), updating the
old acronyms—for example, WYXIWYG, What You eXperience Is What You Get
(Lee, Kim, & Billinghurst, 2005)—and spawning conferences—for example,
DUX, Designing for User Experience. We will see that, in addition to traditional
usability attributes, user experience entails social and cultural interaction,
value-sensitive design, and emotional impact—how the interaction experience
includes “joy of use,” fun, and aesthetics.
A PRACTICAL APPROACH
This book takes a practical, applied, hands-on approach, based on the
application of established and emerging practices, principles, and proven
methods to ensure a quality user experience. The process is about practice,
drawing on the creative concepts of design exploration and visioning to make
designs that appeal to the emotions of users, while also drawing on engineering
concepts of cost-effectiveness—making things as good as the resources permit,
but not necessarily perfect.
The heart of the book is an iterative and evaluation-centered UX lifecycle
template, called the Wheel, for interaction design in Part I: Process. Lifecycle
activities are supported by specific methods and techniques spelled out in
Chapters 3 through 19, illustrated with examples and exercises for you to apply
yourself. The process is complemented by a framework of principles and
guidelines in Part II: Design Infrastructure and Guidelines for getting the right
content into the product. And, throughout, we try to keep our eye on the prize,

the pragmatics of making it all work in your development environment.
ORDER OF THE MATERIAL
We faced the question of whether to present the process first or the design
infrastructure material. We chose to start with the process because the process
contains development activities that should precede design. We could just as
xii PREFACE
well have started with the design infrastructure chapters, especially the
interaction design guidelines, and you can read it in that order, too.
One important reason for covering the process first is a practical
consideration in the classroom. In our experience, we have found it effective to
teach process first so that students can get going immediately on their
semester-long team project. Perhaps their designs might be a little better if
they had the guidelines first, but we find that it does not matter, as their projects
are about learning the process, not making the best designs. Later, when we
do get into the design guidelines, the stud ents appreciate it more because
they have a process structure for where it all goes.
Use the Index
Use the index! We have tried to keep the text free of inter-section references. So,
if you see a term you do not understand, use the index to find out where it is
defined and discussed.
OUR AUDIENCE
This book is not a survey of human–computer interaction, usability, or user
experience. Nor is it about human–computer interaction research. It is a
how-to-do-it handbook, field guide, and textbook for students aspiring to be
practitioners and practitioners aspiring to be better. The approach is practical,
not formal or theoretical. Some references are made to the related science, but
they are usually to provide context to the practice and are not necessarily
elaborated.
Anyone involved in, or wishing to learn more about, creating interaction
designs to ensure a quality user experience will benefit from this book. It is

appropriate for a broad spectrum of readers, including all kinds of practitioners—
interaction designers, graphic designers, usability analysts, software engineers,
programmers, systems analysts, software quality-assurance specialists, human
factors engineers, cogniti ve psychologists, cosmic psychics, trai ners, technical
writers, documentation specialists, marketing personnel, and project managers.
Practitioners in any of these areas will find the hands-on approach of this book
to be valuable and can focus mainly on the how-to-do-it parts.
Researchers in human–computer interaction will also find useful information
about the current state of user interaction design and guidelines in the field.
Software engineers will find this book easy to read and apply because it relates
interaction design processes to those in software engineering.
xiiiPREFACE
Academic readers include teach ers or instructors and students. The
perspectives of student and practitioner are very similar; both have the goal
of learning, only in slightly different settings and perhaps with different
motivations and expectations.
We have made a special effort to support teachers and instructors for use in a
college or university course at the undergraduate or graduate level. We are
especially mindful that many of our teacher/instructor readers might be faced
with teaching this material for the first time or without much background of
their own. We have included, especially in the separate instructor’s guide, much
material to help them get started.
In addition to the material for course content, we have compiled a wide
range of pedagogical and adminis trative support materials, for example, a
comprehensive set of course notes, suggested course calendar, sample syllabi,
project assignments, and even sample course Web pages. The exercises are
adapted easily for classroom use in an ongoing, semester-long set of in-class
activities to design, prototype, and evaluate an interaction design. As instructors
gain the experience with the course, we expect they will tailor the materials, style,
and content to the needs of their own particul ar setting.

We also speak to our audiences in terms of their backgrounds and needs. We
want those working to develop large domain-complex systems in large-scale
projects to have a sufficiently robust process for those jobs. We also want to
address young “UXers” who might think the full process is overly heavy and
engineering-like. We offer multiple avenues to lighter-weight processes. For
many parts of the full process we offer abridged approaches.
In addition, we have added a chapter on rapid evaluation techniques and a
chapter on agile UX methods, paralleling the agile software engineering
processes in the literature. But we want these readers to understand that the
abridged and agile processes they might use for product and small system
development are grounded in full and robust processes used to develop systems
with complex domains. Even if one always takes the abridged or agile path, it
helps to appreciate the full process, to understand what is being abridged. Also,
no matter what part of this book you need, you will find it valuable to see it set in
a larger context.
Some readers will want to emphasize contextual inquiry, whereas others will
want to focus on design. Although many of the process chapters have an
engineering flavor, the design chapter takes on the more “designerly” essence of
design thinking, sketching, and ideation. Others yet will want the heaviest
coverage on evaluation of all kinds, as that is th e “payoff” activity. We take the
xiv PREFACE
approach that the broadest coverage will reach the needs of the broadest of
audiences. Each reader can customize the way of reading the book, deciding
which parts are of interest and ignoring and skipping over any parts that are not.
INCREASING MATURITY OF THE DISCIPLINE AND
AUDIENCE
We are approaching two decades since the first usability engineering process
books, such as Nielsen (1993), Hix and Hartson (1993), and Mayhew (1999),
and human–computer interaction as a discipline has since evolved and matured
considerably. We have seen the World Wide Web mature to become a stock

medium of commerce. The mobile communications revolution keeps users
connected to one another at all times. New intera ction techniques emerge and
become commonplace overnight to make the users’ information literally a
“touch” away.
Despite all these technological advances, the need for a quality user
experience remains paramount. If anything, the importance of ensuring a
positive user experience keeps increasing. Given the pervasive information
overload, combined with the expectation that everyone is computer savvy, the
onus on designing for a quality user experience is even more critical these days.
Among all these advances, many of the concepts of existing design and
development paradigms are more or less unchanged, but emerging new
paradigms are stretching our understanding and definition of our primary
mandate—to create an interaction design that will lead to a quality user
experience. Approaches to accomplish this mandate have evolved from
engineering-oriented roots in the early 1990s to more design-driven
techniques today.
Although much has been added to the literature about parts of the
interaction development process, the process is still unknown to many and
misunderstood by many and its value is unrecognized by many. For example,
many still believe it is just about “usability testing.”
Since our first book (Hix & Hartson, 1993), we have conducted many short
courses and university courses on this material, working with literally hundreds
of students and user experience practitioners at dozens of locations in business,
industry, and government. We have learned quite a bit more about what works
and what does not.
It is clear that, in this same period of time, the level of sophistication among
our audiences has increased enormously. At the beginning we always had to
xvPREFACE
assume that most people in our classes had no user experience background, had
never heard of user experience specialists, and, in fact, needed some motivation

to believe in the value of user experi ence. As time went on, we had to adjust the
short course to audiences that required no motivation and audiences
increasingly knowledgeable about the need for quality user experience and what
was required to achieve it. We started getting user experience specialists in the
class—self-taught and graduates of other user experience courses.
WHAT WE DO NOT COVER
Although we have attempted a broad scope of topics, it is not possible to include
everythinginonebook,noris itwiseto attemptit.Weapologizeifyourfavoritetopic
is excluded, but we had to draw the line somewhere. Further, many of these
additionaltopicsaresobroad in themselvesthatthey cannotbecovered adequately
in a section or chapter here; each could (and most do) fill a book of their own.
Among the topics not included are:
n Accessibility and the American Disabilities Act (ADA)
n Internationalization and cultural differences
n Ergonomic health issues, such as repetitive stress injury
n Specific HCI application areas, such as societal challenges, healthcare systems, help
systems, training, and designing for elders or other special user populations
n Special areas of interaction such as virtual environments or 3D interaction
Additionally, our extensive di scussions of evaluation, such as usability testing,
are focused on formative evaluation, evaluation used to iteratively improve
interaction designs. Tutorials on performing summative evaluation (to assess a
level of performance with statistically significant results) are beyond our scope.
ABOUT THE EXERCISES
The Exercises Are an Integral Part of the Course Structure
A Ticket Kiosk System is used as an ongoing user interaction development
example for the application of material in examples throughout the book. It
provides the “bones” upon wh ich you, the reader or student, can build the flesh
of your own design for quality user experience. In its use of hands-on exercises
based on the Ticket Kiosk System, the book is somewhat like a workbook. After
xvi PREFACE

each main topic, you get to apply the new materi al immediately, learning the
practical techniques by active engagement in their application.
Take Them in Order
As explained earlier, we could have interchanged Part I and Part II; either part
can be read first. Beyond this option, the book is designed mainly for sequential
reading. Each process chapter and each design infrastructure chapter build on
the previous ones and add a new piece to the overall puzzle. Because the material
is cumulative, we want you to be comfortable with the material from one chapter
before proceeding to the next. Similarly, each exercise builds on what you
learned and accomplished in the previous stages—just as in a real-world project.
For some exercises, especially the one in which you build a rapid prototype,
you may want to spread the work over a couple of days rather than the couple of
hours indicated. Obviously, the more time you spend working on the exercises,
the more you will understand and appreciate the techniques they are designed
to teach.
Do the Exercises in a Group if You Can
Developing a good interaction design is almost always a collaborative effort, not
performed in a vacuum by a single individual. Working through the exercises
with at least one other interested person will enhance your understanding and
learning of the materials greatly. In fact, the exercises are written for small teams
because most of these activities involve multiple roles. You will get the most out
of the exercises if you can work in a team of three to five people.
The teamwork will help you understand the kinds of communication,
interaction, and negotiation that take place in creating and refining an
interaction design. If you can season the experience by including a software
developer with responsibi lity for software architecture and implementation,
many new communication needs will become apparent.
Students
If you are a student in a course, the best way to do the exercises is to do them in
teams, as in-class exercises. The instructor can observe and comment on your

progress, and you can share your “lessons learned” with other teams.
Practitioners: Get buy-in to do the exercises at work
If you are a practitioner or aspiring practitioner trying to learn this material in
the context of your regular work, the best wa y of all is an intensive short course
with team exercises and projects. Alternatively, if you have a small interaction
xviiPREFACE
design team in your work group, perhaps a team that expects to work together
on a real project, and your work environment allows, set aside some time (say,
two hours every Friday afternoon) for the team exercises. To justify the extra
overhead to pull this off, you will probably have to convince your project
manager of the value added. Depending on whether your manager is already UX
literate, your justification may have to start with a selling job for the value of a
quality user experience (see Chapter 23).
Individuals
Do not let the lack of a team stop you from doing the exercises. Try to find at
least one other person with whom you can work or, if necessary, get what you can
from the exercises on your own. Although it would be easy to let yourself skip the
exercises, we urge you to do as much on each of them as your time permits.
PROJECTS
Students
Beyond the exercises, more involved team projects are essential in a course on
development for a quality user experience. The course behind this book is, and
always has been, a learn-by-doing course—both as a university course and in all
of our short courses for business and industry.
In addition to the small-scale, ongoing example application used by teams as a
series of in-class activities in conjunction with the book exercises, we cannot
emphasize enough the importance of a substantial semester-long team project
outside of class, using a real client from the community—a local company, store,
or organization that needs some kind of interactive software application
designed. The client stands to get some free consulting and even a system

prototype in exchange for serving as the project client.
Instructors: See the instructor’s guide for many details on how to organize
and conduct these larger team projects. The possibilities for project applications
are boundless; we have had students develop interaction designs for all kinds of
applications: electronic mail, an interactive Monopoly game, a personnel
records system, interactive Yellow Pages, a process control system, a circuit
design package, a bar-tending aid, an interactive shopping cart, a fast-food
ordering system, and so on.
Practitioners
As a way of getting started in transferring this material to your real work
environment, you and your existing small team can select a low-risk project. You
or your co-workers may already be familiar and even experienced with some of
xviii PREFACE
those activities and may even already be doing some of them in your
development environment. By making them part of a more complete and
informed development lifecycle, you can integrate what you know with new
concepts presented in the book.
For example, many development teams use rapid prototyping. Nonetheless,
many teams do not know how to make a low-fidelity prototype (as opposed to
one programmed on a computer) or do not know what to do with such a
prototype once they have one. Many teams bring in users and have them try out
the interaction design, but teams often do not know what data are most
important to collect during user sessions and do not know the most effective
analyses to perform once they have collected those data. Many do not know
about the most effective ways to use evaluation data to get the best design
improvements for the money. And very few developers know about measurable
user experience targets—what they are, how to establish them, and how to use
them to help improve the user experience of an interaction design and to
manage the process. We hope this book will help you answer such questions.
ORIGINS OF THE BOOK

Real-World Experience
Although we have been researchers in human–computer interaction, we both
have been also teachers and practitioners who have successfully used the
techniques described in this book for real-world development projects, and we
know of dozens, if not hundreds, of organizations that are applying this material
successfully.
One of us (RH) has been teaching this material for 30 years in both a
university setting and a short course delivered to hundreds of practitioners in
business, industry, government, and military organizations. Obviously a much
broader audience can be reached by a book than can be taught in person, which
is why we have written this book. Because this book is rooted in th ose courses, the
material has been evaluated iteratively and refined carefully through many
presentations over a large number of years.
Research and Literature
In the Department of Computer Science at Virginia Tech, we (RH and
colleagues) established one of the pioneering research programs in
human–computer intera ction back in 1979. Over the years, our work has had
the following two important themes.
xixPREFACE
•
Getting usability, and now UX, right in an interaction design requires an effective
development process integrated within larger software and systems development
processes.
•
The whole point of work in this discipline, including research, is to serve effective
practical application in the field.
The first point implies that human–computer interaction and designing for
user experience have strong connections to software and systems engineering.
Difficulties arise if human–computer interaction is treated only as a psychology
or human factors problem or if it is treated as only a computer science problem.

Many people who enter the HCI area from computer science do not bring to the
job an appreciation of human factors and the users. Many people who work in
human factors or cognitive psychology do not bring an appreciation for
problems and constraints of the software engineering world.
The development of high-quality user interaction designs depends on
cooperation between the roles of design and implementation. The goals of
much of our work in the past decade have been to help (1) bridge the gap
between the interaction design world and the software implementation world
and (2) forge the necessary connections between UX and software engineering
lifecycles.
The second defining theme of our work over the past years has been
technology exchange between academia and the real world—getting new
concepts out into the real world and bri nging fresh ideas from the field of praxis
back to the drawing boards of academia. Ideas from the labs of academia are just
curiosities until they are put into practice, tested and refined in the face of real
needs, constraints, and limitations of a real-world working environment.
Because this book is primarily for practitioners, however, it is not formal and
academic. As a result, it contains fewer references to the literature than would a
research-oriented book. Nonetheless, essential references have been included;
after all, practitioners like to read th e literature, too. The work of others is
acknowledged through the references and in the acknowledgments.
AROUSING THE DESIGN “STICKLER” IN YOU
We are passionate about user experience, and we hope this enthusiasm will take
hold within you, too. As an analogy, Eats, Shoots, & Leaves: The Zero Tolerance
Approach to Punctuation by Lynn Truss (2003) is a delightful book entirely about
punctuation—imagine! If her book rings bells for you, it can arouse what she
xx PREFACE
calls your inner punctuation stickler. You will become particular and demanding
about proper punctuation.
With this book, we hope to arouse your inner design stickler. We could think

of no happier outcome in our readers than to have examples of poor interaction
designs and correspondingly dreadful user experiences trigger in you a ghastly
private emotional response and a passionate desire to do something about it.
This book is for those who design for users who interact with almost any kind
of device. The book is especially dedicated to those in the field who get “hooked
on UX,” those who really care about the user exp erience, the user experience
“sticklers” who cannot enter an elevator without analyzing the design of the
controls.
FURTHER INFORMATION ON OUR WEBSITE
Despite the large size of this book, we had more material than we could fit into
the chapters so we have posted a large number of blog entries about additional
but related topics, organized by chapter. See this blog on our Website at
TheUXBook.com. At this site you will also find additional readings for many of
the topics covered in the book.
ABOUT THE AUTHORS
Rex Hartson is a pioneer researcher, teacher, and practitioner–consultant in
HCI and UX. He is the founding faculty member of HCI (in 1979) in the
Department of Computer Science at Virginia Tech. With Deborah Hix, he was
co-author of one of the first books to emphasize the usability engineering
process, Developing User Int erfaces: Ensuring Usability Through Product & Process.
Hartson has been principal investigator or co-PI at Virginia Tech on a large
number of research grants and has published many journal articles, conference
papers, and book chapters. He has presented many tutorials, invited lectures,
workshops, seminars, and international talks. He was editor or coeditor for
Advances in Human–Computer Interaction, Volumes 1–4, Ablex Publishing Co.,
Norwood, New Jersey. His HCI practice is grounded in over 30 years of
consulting and user experience engineering training for dozens of clients in
business, industry, government, and the military.
Pardha S. Pyla is a Senior User Experience Specialist and Lead Interaction
Designer for Mobile Platforms at Bloomberg LP. Before that he was a researcher

and a UX consultant. As an adjunct faculty member in the Department of
xxiPREFACE
Computer Science at Virginia Tech he worked on user experience
methodologies and taught graduate and undergraduate courses in HCI and
software engineering. He is a pioneering researcher in the area of bridging the
gaps between software engineering and UX engineering lifecycle processes.
xxii PREFACE
Acknowledgments
I (RH) must begin with a note of gratitude to my wife, Rieky Keeris, who
provided me with a happy environment and encouragement while writing this
book. While not trained in user experience, she playfully engages a well-honed
natural sense of design and usability with respect to such artifacts as elevators,
kitchens, doors, airplanes, entertainment controls, and road signs that we
encounter in our travels over the world. You might find me in a lot of different
places but, if you want to find my heart, you have to look for wherever
Rieky is.
I (PP) owe a debt of gratitude to my parents and my brother for all their
love and encouragement. They put up with my long periods of absence from
family events and visits as I worked on this book. I must also thank my brother,
Hari, for being my best friend and a constant source of support as I worked on
this book.
We are happy to express our appreciation to Debby Hix, for a careeer-long
span of collegial interaction. We also acknowledge several other individuals with
whom we’ve had a long-term pro fessional association and friendship at Virginia
Tech, including Roger Ehrich, Bob and Bev Williges, Tonya Smith-Jackson, and
Woodrow Winchester. Similarly we are grateful for our collaboration and
friendship with these other people who are or were associated with the
Department of Computer Science: Ed Fox, John Kelso, Sean Arthur, Mary Beth
Rosson, and Joe Gabbard. We are also grateful to Deborah Tatar and Steve
Harrison of the Center for Human-Computer Interaction at Virginia Tech

for steering us to consider more seriously the design thinking paradigm
of HCI.
We are indebted to Brad Myers of Carnegie Mellon University for the use of
ideas, words, examples, and figures in the contextual inquiry and modeling
chapters. Brad was instrumental in the evolution of the material in this book
through his patient adoption of and detailed feedback from early and
incomplete trial versions.
In addition, we wish to thank Janet Davis of Grinnell College for her adoption
of an early draft of this book and for her detailed and insightful feedback.
Thanks also to Jon Meads of Usability Architects, Inc. for help with ideas for
the chapter on agile UX methods and to John Zimmerman of CMU for
suggesting alternative graphical representations of some of the models.
Additionally, one paragraph o f Chapter 4 was approved by Fred Pelton.
Susan Wyche helped with discussions and introduced us to Akshay Sharma, in
the Virginia Tech Department of Industrial Design. Very special thanks to
Akshay for giving us personal access to the operations of the Department of
Industrial Design and to his approach to teaching ideation and sketching.
Akshay also gave us access to photograph the ideation studio and working
environment there, including students at work and the sketches and prototypes
they produced. And finally our thanks for the many photographs and sketch es
provided by Akshay to include as figures in design chapters.
It is with pleasure we acknowledge the positive influence of Jim Foley, Dennis
Wixon, and Ben Shneiderman , with whom friendship goes back decades and
transcends professional relationships.
We thank Whitney Quesenbery for discussions of key ideas and
encouragement to keep writing. Thanks also to George Casaday for many
discussions over a long-term friendship. We would like to acknowledge Elizabeth
Buie for a long and fruitful working relationship and for helpful discussions
about various topics in the book. And we must mention Bill Buxton, a friend and
colleague who was a major influence on the m aterial about sketching and

ideation.
We are grateful for the diligence and professionalism of the many, many
reviewers over the writing lifecycle, for amazingly valuable suggestions that have
helped make the book much better than what it started out to be. Especially to
Teri O’Connell and Deborah J. Mayhew for going well beyond the call of duty in
detailed manuscript reviews.
We wish to thank the Department of Computer Science at Virginia Tech for
all the support and encouragement.
Among those former students especially appreciated for volunteering untold
hours of fruitful discussions are Terence Andre, Steve Belz, and Faith McCreary.
I (RH) enjoyed my time working with you three and I appreciate what you
contributed to our discussions, studies, and insights.
Susan Keenan, o ne of my (RH) first Ph.D. students in HCI, was the one
who started the User Action Framework (UAF) work. Jose (Charlie) Castillo
and Linda van Rens are two special friends and former research
collaborators.
We wish to thank all the HCI students, including Jon Howarth and Miranda
Capra, we have had the pleasure of working with over the years. Our discussions
xxiv ACKNOWLEDGMENTS