The Project Management Body of Knowledge classifies projects into stages that correspond to their life cycles, beginning with Project Initiation and ending with Project Closure. There are goals, processes, deliverables, and milestones defined for each stage of the project management life cycle. Better organizational control over the projects they handle can be achieved through phase-based management, which gives the project team a common language to communicate project progress. A project's phase represents a distinct period during which a group of tasks are performed together under the supervision of the project manager. Phases in a project's life cycle typically follow one another in a linear fashion, with the completion of one or more deliverables marking the end of each phase.