Slide 4 of 17
Notes:
Kent provided a list of the 12 or 13 XP Practices in the sidebar to his original paper reprinted in the IEEE Dynabook: Feel free to read over the quick summary’s of each of the major practices in XP.
Jawed Siddiqi states in, An Exposition of XP But No Position on XP, "For me, the best way to understand Beck’s explanation of XP is in terms of a project management strategy and a development strategy, each of which comprises a set of practices. XP assumes that the four project variables of cost, time, scope, and quality can be controlled.”
Siddiqi goes on to explain that XP assumes currently available tools and practices can be used to control the four project variables. This assumption is contrary to one of the universal software engineering assumptions; the cost of changing a software system over time grows exponentially. Barry Boehm in Software Engineering Economics states, a dollar to fix a problem in a system at requirements might cost thousands after production. The four management strategies are present in some fashion in most methodologies: Customer onsite, Short release, Metaphors and, the Planning game.
Eight of the 12 XP practices describe XP’s development strategy. Four of these depart from other methodologies’ practices: 40-hour workweek, Pair Programming, Collective ownership, and Open workspace. Largely in accord with established good practices are the remaining 4: simple design, coding standards, testing and refactoring.
