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64 Chapter 3 Agile software development

developers to the support team. However, supporters of agile methods rightly
argue that documentation is frequently not kept up to date and it is not of much
use for long-term system maintenance.
6. What technologies are available to support system development? Agile methods
often rely on good tools to keep track of an evolving design. If you are develop-
ing a system using an IDE that does not have good tools for program visualiza-
tion and analysis, then more design documentation may be required.
7. How is the development team organized? If the development team is distributed
or if part of the development is being outsourced, then you may need to develop
design documents to communicate across the development teams. You may
need to plan in advance what these are.
8. Are there cultural issues that may affect the system development? Traditional
engineering organizations have a culture of plan-based development, as this is
the norm in engineering. This usually requires extensive design documentation,
rather than the informal knowledge used in agile processes.
9. How good are the designers and programmers in the development team? It is
sometimes argued that agile methods require higher skill levels than plan-based
approaches in which programmers simply translate a detailed design into code.
If you have a team with relatively low skill levels, you may need to use the best
people to develop the design, with others responsible for programming.
10. Is the system subject to external regulation? If a system has to be approved by an
external regulator (e.g., the Federal Aviation Authority [FAA] approve software
that is critical to the operation of an aircraft) then you will probably be required
to produce detailed documentation as part of the system safety case.

In reality, the issue of whether a project can be labelled as plan-driven or agile is
not very important. Ultimately, the primary concern of buyers of a software system
is whether or not they have an executable software system that meets their needs and
does useful things for the individual user or the organization. In practice, many com-
panies who claim to have used agile methods have adopted some agile practices and
have integrated these with their plan-driven processes.

3.3 Extreme programming

Extreme programming (XP) is perhaps the best known and most widely used of the
agile methods. The name was coined by Beck (2000) because the approach was
developed by pushing recognized good practice, such as iterative development, to
‘extreme’ levels. For example, in XP, several new versions of a system may be devel-
oped by different programmers, integrated and tested in a day.