The term project phase refers to a collection of activities within a project. Each project phase is goal-oriented and ends at a milestone. Reaching these milestones means the project progresses. Each phase can be divided into sub-phases. The project plan (e. g. a project network diagram) clarifies the systematic hierarchy of the individual phases and establishes dependencies among them.
If the project phases are planned sequentially, the term waterfall model is used for that kind of project planning. Each phase is scheduled after the other and they do not overlap. In reality, many project phases overlap and the visualization of the phases in a Gantt-chart makes dependencies, constraints and the critical path more transparent.
If project phases are part of an iterative project plan, e. g. in agile project management, the individual phases can overlap as individual steps or tasks from one phase can be adopted in another phase for optimization.
Typical project phases are:
In contrast to the project phases, the so-called service phases in construction project management in Germany are based on the fee regulations for architects and engineers (HOAI). They are very clearly defined and include basic services as well as additional services.