Preface

If the Unified Software Development Process (USDP) were a coloring book, I'm afraid I'd be characterized as one of those kids who just can't color within the lines. I've been using use-case-like "things" for quite some time, although they may have been called something else: workflows, scenarios when Object Modeling Technique (OMT) came out, and then eventually use cases. But the funny thing is, more often than not I wasn't using them like the USDP described them being used. Rather, I was combining them first with this technique, and then that one. It's not that I was trying to be a rebel; use cases just seemed to fit in nicely with other techniques to solve a problem. Eventually, as the USDP matured, I began to notice that others were starting to mention QFD in conjunction with use cases and discuss operational profiles of use cases. Scott Ambler added project portfolio management to his Enterprise Unified Process, an extension to USDP; and preconditions and postconditions actually became an official part of use cases. It finally occurred to me: other people were coloring outside the lines too! The motivation for this: problems that were best solved with techniques that were not a part of USDP proper; problems for which other disciplines already had solutions.

It was this realization that led to this book: that my experiences with disciplines, such as QFD, Software Reliability Engineering, Model-based Specification (preconditions, postconditions, and invariants), Requirements Configuration Management, and Project Portfolio Management combined with use cases might benefit others in the use case development community.

This book presents what I hope you will agree is a whole new set of perspectives on use case-driven development. Innovation, solutions to problems, and ways of working smarter often arise when ideas from multiple areas are combined. As use cases continue to mature, future improvements in use case-driven development are likely to arise from just such cross-pollination of use cases with other disciplines of software engineering. This book looks at four areas that focus on quality engineering.

1. Quality Function Deployment (QFD)

2. Software Reliability Engineering

3. Model-Based Specification (Preconditions, Postconditions, and Invariants)

4. Requirements Configuration Management/Project Portfolio Management

From each discipline, the book pulls practical, 20/80, "high bang for the buck" ideas that help you and your organization work smart to deliver quality products in use case-driven development.^[1]

^[1] "Quality" as used in this book is the project stakeholders' (especially customers') relative valuation of scope (functions and features), schedule (speed of delivery to the customer), cost and degree of defect-free operation (i.e. reliability). This is the same definition used by Jim Highsmith (2000) and others in the software quality arena.