Phase-To-Phase Relationships

A large project may be broken into specific phases, with each of these phases having specific deliverables. At the end of a phase, a Phase-End Review may occur, which formally concludes that phase, and if the project is deemed worthwhile to continue, authorizes the next phase to begin. There are three major phase-to-phase relationships described in the PMBOK®:

• Sequential Relationship. Here when one phase is complete, the next phase may begin.
• Overlapping Relationship presents that the next phase may begin before the previous phase is completely finished
• Iterative Relationship is useful for largely undefined projects. Planning for the next phase occurs during the current phase

Project may have more than one of these relationships. For example, the early phases may have been performed sequentially, but due to falling behind schedule, later phases will be overlapped.