Scope control and buffer

Agile methods such as Scrum emphasize scope control of Sprints(iterations). It is equally important to control scope with regards to the MDE release. A project that always is one iteration from releasing risks loosing all credibility. Controlling the size of the MDE results in some very difficult trade-offs. The multiple iterations within the MDE will produce some very high priority issues. Balancing these against the cost of growing the MDE is not easy. Reserving a buffer of about 10% for issues that are identified during iterations is highly recommended.

There is no conflict between the Scrum practice of not having buffers in Sprints and buffering a release. Releases will often have a fixed date. There is no point in releasing on the agreed date without essential features that have been identified in the Sprints leading up to the release.