Table Of ContentHofmann
Requirements Engineering
GABLER EDITION WISSENSCHAFT
Information Engineering und
IV -Controll in g
Herausgegeben von
Professor Dr. Franz Lehner,
Universität Regensburg (schriftführend),
Professor Dr. Stefan Eicker,
Universität-GH Essen,
Professor Dr. Ulrich Frank,
Universität Koblenz-Landau,
Professor Dr. Erich Ortner,
Technische Universität Darmstadt,
Professor Dr. Eric Schoop,
Technische Universität Dresden
Die Schriftenreihe präsentiert aktuelle Forschungsergebnisse der
Wirtschaftsinformatik sowie interdisziplinäre Ansätze aus Informatik
und Betriebswirtschaftslehre. Ein zentrales Anliegen ist dabei die
Pflege der Verbindung zwischen Theorie und Praxis durch eine an
wendungsorientierte Darstellung sowie durch die Aktualität der Bei
träge. Mit der inhaltlichen Orientierung an Fragen des Information
Engineerings und des IV-Controllings soll insbesondere ein Beitrag zur
theoretischen Fundierung und Weiterentwicklung eines wichtigen
Teilbereichs der Wirtschaftsinformatik geleistet werden.
Hubert F. Hofmann
Requirements
Engineering
A Situated Discovery Process
With foreword by
0
Prof. Dr. Franz Lehner
Springer Fachmedien Wiesbaden GmbH
Die Deutsche Bibliothek -ClP-Einheitsaufnahme
Hofmann, Hubert F.:
Requirements engineering : o situated discovery process.
/ Hubert F. Hofniann. With o forew. by Franz Lehner.
-Wiesbaden : Dt. Univ. -VerI. ; wiesbaden : Gabler, 2000
(Gobler Edition WissenschaFt : Information Engineering und IV-Controlling)
Zugl.: Regensburg, Univ., Diss., 2000
ISBN 978-3-8244-7215-4
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Fo r my mother and Theresa
Foreword
In general the subject of requirements engineering is dealt with as the first stage in
the life cyc1e or in the process of software development. Due to rapid advancements in
the field of software technologies, the technicalliterature to date does not represent the
elicitation and documentation of requirements as comprehensively as to meet its
importance. Thus, an increasing demand and a considerable deficit persists in research.
Meanwhile, deviations from estimates (e.g., time and expenses), when developing or
procuring software products, is an everyday occurrence. A substantial part of this is
due to underestimating expenditures during early project stages, in particular for the
analysis of requirements. Additionally, errors and failures during these early project
stages cause exceptionally high expenses for adjustments of already delivered
software. The importance of requirements engineering stands vis-a-vis to insufficient
knowledge about available techniques and the methodological approach in practice.
Since the beginning of the seventies, when the discussion about the software crisis
started, the knowledge in this field significantly increased. This book is, therefore, of
considerable importance.
An important contribution ofthe author consists ofa comprehensive overview ofthe
state of technology and knowledge in this field. In this context the gap between theory
and practice, frequently quoted in the technical literature, is also dealt with. Building
upon this the author analyzes current practice by reviewing the few studies, which are
available for that purpose. Time and again an insufficient relation of requirements
knowledge, resources, and process to the situation proves to be the weak point. But
only with such a relation an adequate consideration of the participating persons and
the evolving application situation is ensured. To bridge this gap, the author compiles
heuristics to improve the current practice of requirements engineering (situated
discovery process). Finally, in a field study, the verification ofthe suggested concepts
and heuristics is attempted. In summary it can be maintained that a comprehensive
work to areal and relevant subject has been presented. It is an effective reflection of
the relevant literature and a diversified illustration of requirements engineering, which
has previously been nonexistent in this form, and which deserves an adequate positive
reception among experts.
Prof. Dr. Franz Lehner
Preface
Specifying requirements, often called requirements engineering (RE), may be the
single most important part of a software project. Frequently, however, it is the
detrimental impact of deficient requirements that emphasizes RE's significant role in
deve10ping or procuring software. Originally, RE set out to correct this situation by
bringing an engineering orientation to traditional system analysis. This resulted in a
piethora ofmethods and techniques emphasizing fitness-of-form. That is, they focused
on the internal consistency of a specification against the demands of the specification
language or the consistency of a pro gram with its formal specification. Practitioners
were left with little guidance on how to apply these methods and techniques to
successfully specify requirements.
Research, however, increasingly c10ses the gap to RE practice. Ihis more
comprehensive view of RE allows stakeholders to achieve and maintain a common
understanding of the problem and its solution over the software's life cyc1e. In other
words, fitness-for-purpose and fitness-for-change receive more attention. Fitness-for
purpose ensures the software's conformity with social and technical requirements. It
indicates the understanding of requirements at a given time and deals with the
specification's completeness typically measured against some standard, guideline, or
domain model. Fitness-for-change denotes the capability to systematically adapt the
specification to achanging environment.
We expand on previous research and explore fitness-for-purpose and fitness-for
change to emphasize a more comprehensive understanding of specifying software. Io
achieve this understanding, we first c1assify prevalent methods for each RE activity
and compile "heuristics" to help stakeholders identify useful methods for developing
or procuring software. We also review five processes that prescribe the timing and
frequency of RE activities throughout the software process. While these processes
subscribe to different assumptions, they view RE as a fundamentally social process
that involves reciprocal interactions of stakeholders, teams, and specifications. In other
words, they emphasize that RE is a discovery process.
We then turn to the scarce empirical evidence ofRE in practice. For that, we review
seven field studies. Ihey offer a wide variety of findings addressing a diverse set of
issues largely confirming most people's intuitions and experiences about specifying
x Preface
requirements. Nevertheless, they also teach us that the commonly experienced
discrepancy between the stakeholders' expectations and their (partial) realization in
the form of software is deeply rooted in the practiced process of discovering
requirements. Moreover, they clearly emphasize RE as a leaming, communication, and
negotiation process. While the reviewed studies guide us in the right direction, they
pinpoint the need to integrate technical process models with cognitive, social, and
organizational processes to improve RE.
Based on these findings, we establish RE as a situated discovery process. To develop
the foundations of situatedness, we first outline the theory of structuration. Giddens
(1984) provides a situated perspective that integrates technical aspects with the
(human) environment in which software is initiated, operated, and evaluated. The
situated perspective sees a stakeholders' actions as embedded and indexically related
to the situation. It stresses the situated character of human action and emphasizes the
relevance of context, experience, and practice in RE. In other words, stakeholders
draw on knowledge, resources, and processes when specitying software.
We apply this situated framework in an exploratory field study. It considers
knowledge, allocated resources, and exhibited RE processes, as weIl as discusses their
contribution to a project's success or failure. We discuss the stakeholders' assessment
ofRE team knowledge with regard to the application domain, information technology,
and the RE process. We also review resource utilization and RE processes deployed by
participating projects. FinaIly, we provide an overview oftheir performance in terms
ofthe quality ofRE service, the quality ofRE products, and process contro!. Some RE
teams perform significantly better than the majority of participating projects. In
general, they successfully "maneuver" through the duality of structure and
dynamically balance its modalities (Le., knowledge, resources, and process).
Preface XI
Acknowledgements
The research for this book on requirements engineering started some seven years
ago. Hence, my gratitude is spread far and wide. Old friends as weil as complete
strangers from various disciplines have provided invaluable assistance combined with
criticism and creative suggestions.
The central themes of this work have their roots in the practices of leading high
technology companies. While these companies and the outstanding executives that
manage their software development and procurement must go unnamed, I am deeply
indebted to them for inspiring me to think in new and ever-evolving ways.
I owe a debt of gratitude to many colleagues and teachers from whom I have learned
so much over the years. Franz Lehner, my friend and thesis advisor, was critically
important to this project. I have been privileged to have his expert suggestions and
support. I would also like to thank Dieter Bartmann and the late Gerhard Niemeyer for
supporting this work.
Many of the ideas in this work have emerged from informal discussions. We would
particularly like to thank Jon Bartol, Bruce Blum, Bill Clancey, Anthony Finke1stein,
Norbert Fuchs, Ralph Holbein, Johannes Koch, Julio Cesar Leite, John Marano, John
Overmars, Rolf Pfeifer, Gustav Pomberger, Colin Potts, Gerald Quirchmayr, and
Dennis Severance.
Finally and most importantly I want to thank my family for their love and support
during these many years. A special thanks goes to my wife, Theresa, for arranging our
lives to accommodate this whole project, for ingeniously facilitating "thinking"
workshops to keep ideas flowing, and who always gently shows me that there is a rich
life beyond all things related to requirements engineering. I end with deepest thanks to
my mother, Elfriede, who inspired much of the enthusiasm and discipline that went
into the creation ofthis book.
Hubert F. Hofmann
