This a free monthly newsletter providing software book reviews and commentary on software industry
trends for the wider business community by Marcus Price, Agilier Ltd, March 2006
Overview
This is an excellent introductory book to the rapidly-growing world of "Agile" software development
processes. The book describes:
- what is meant by the term "Agile"
- why traditional software development processes are leading to problems and how Agile processes
seek to address these
- an overview of the different types of Agile processes
- details on the most popular and most interesting Agile processes
- a series of Questions and Answers.
Background
Although not a new phenomenon, Agile processes have been given a new lease of life after the
perceived failure of traditional "Waterfall" process. Waterfall processes are typically
characterised by a heavy emphasis on documentation with requirements being frozen before development
starts and with the whole project planned upfront.
This approach of mandating that no requirements be allowed leads to inflexibility in the face of
business change. In addition, if the project was a large one, delivery of software may occur years
after the requirements are signed off. This, coupled with a characteristic lack of stakeholder
involvement during development, led to systems being developed that did not truly address the
stakeholders’ business needs.
Agile processes seek to address these problems by allowing requirements change (in some cases
throughout the lifecycle of the project) and that the software is delivered in successive
iterations. In addition, the stakeholders are closely involved in the development of the project.
Notably, it is the stakeholders, rather than the developers, that decide which of the requirements
is built first. At the end of the iteration, the newly-written software is demonstrated to the
stakeholders. Such regular deliveries and close involvement ensures that development does not
deviate too far from the stakeholders’ requirements.
Larman describes three of the most popular recent software development approaches: Extreme
Programming (XP), the Unified Process (UP), Scrum; and an older, less popular one, Evo.
XP
XP is the most well known and notorious of all Agile processes – it was this that kick-started the
modern Agile process movement around the year 2000; but Agile processes have been around much
longer. XP is characterised by its very short incremental delivery periods (between one and three
weeks), emphasis on having a full-time on-site stakeholder and pair programming.
This last aspect has given XP (among developers) its love-it or hate-it reputation. This is where
two developers share a one workstation and jointly develop a part of the system; the idea that two
people working simultaneously reduces the number defects (bugs) are produced. This can be a big
culture change for developers, especially those that are used to working for long periods on their
own. Larman gives figures to show that the pair programming approach dramatically reduces the number
of defects and how to overcome resistance to the introduction of this practice.
UP
UP is a very popular iterative process framework, particularly its commercial refinement - the
Rational Unified Process (RUP). UP/RUP is an extremely comprehensive process framework that was
introduced in the late 1990s. It is designed as a framework to be adapted for use on all types of
project from the simplest to the most complex.
This very flexibility has led the unwary to use the full framework for all types of project, leading
to an over-emphasis on documentation. There is also a widespread belief that the framework is simply
a modern restatement of the Waterfall process, bringing all its associated problems. In the book,
Larman shows very clearly that by using UP/RUP process correctly, ie as a framework than can be
configured differently for different projects, that it can be used in an agile way.
Scrum
Scrum can be regarded as an Agile project management process rather than a software development
process. It is characterised by one-month iterations and daily stand-up meetings where the whole
team briefly discuss progress and problems. It does not mandate any particular development style;
for example, it is silent on whether pair programming should be used or not. Hence, it is ideally
suited as project management "wrapper" to other Agile processes - most usually XP.
Evo
Evo is a surprising choice for this book. It is an older process, dating from the 1960s, and has
popularity in niche areas such as aircraft manufacture. Larman says that he includes it to show that
agile processes are not a new phenomenon. Evo has some interesting features, most notably a good way
of defining non-functional requirements and is worth investigating as a potential agile approach for
large system development programmes.
Book Strengths
As well describing the features, pros and cons of each, Larman gives advice on which process is best
used for different project circumstances. This is absolutely the key point; there is no
one-size-fits-all process – one has to examine the circumstances surrounding the project and then
choose the process accordingly. In this respect, Larman’s book is invaluable – he provides guidance
on this choice with statistical evidence to support his advice.
He also gives practical advice on circumventing one of the main criticisms of some Agile processes –
namely that they do not scale well. For example, Larman describes techniques for using Agile
approaches for multiple, geographically dispersed teams. One suggested approach is for the first two
iterations to be run with one central team as usual; then this team splits up and "seeds" other
teams for subsequent iterations. Larman also discusses how five-team project, located on separate
sites across sixteen time zones, was able to work in an agile, iterative manner from the outset.
The book concludes with one of its most useful sections - a series of answers to questions that an
attentive reader may have, for example "How to adopt an iterative, Agile process within an existing
waterfall process culture?" The approaches suggested are ones in which my company specialises.
Verdict
Although this book is described as "A Manager’s Guide", it is an excellent introduction for business
leaders that have had problems with traditional software development processes, that have heard of
Agile processes as a possible solution, and would like to find out more. It is also an excellent
reference for those who have practised Agile processes and would either like to improve their
knowledge or would like to find solid evidence-based support to influence others.
This a free monthly newsletter providing software book reviews and commentary on software industry
trends for the wider business community.
Please feel free to send comments or forward this to colleagues and friends who will find it
valuable. Permission is granted to reprint as long as it is reprinted in its entirety.
Agilier is an independent consultancy specialising in providing leading-edge
business-change and technology services using Agile techniques.
Copyright (c) 2006 by Marcus Price
