What makes XP different?
Its early, concrete, and continuing feedback from short cycles.
Its incremental planning approach, which quickly comes up with an overall plan that is expected to evolve through the life of the project.
Its ability to flexibly schedule the implementation of functionality, responding to changing business needs.
Its reliance on automated tests to demonstrate the presence of features.
Its reliance on oral communications, tests, and source code to communicate system structure and intent.