There are two distinct but related life cycles: the product lifecycle and the project life cycle.
The product lifecycle compasses all the activities related to a product from inception until it is divested.
This might include research and development, feasibility studies, product development, enhancements, training, upgrades, and ongoing maintenance.
Even intangible products, like services or results, follow a similar generic life cycle.
The project life cycle is one element of the product lifecycle since there are normally many projects involved in a product’s lifespan.
The project life cycle encompasses only those activities related to the project's purpose.
Characteristics of the Project Life Cycle
Projects vary in size and complexity.
No matter how large or small, simple or complex, all projects can be mapped to the following life cycle:
- Starting the project,
- Organizing and preparing,
- Carrying out the project work, and
- Closing the project.
The flow of the project life cycle gives us some insights into what can generally be expected.
Costs and staffing levels are lowest early in the life cycle, peak while the project work is underway, and then drop off as the project nears completion.
This behavior is because the bulk of the work required to develop the project’s primary deliverables will take place in the middle of the project.
A risk is highest early in the project since uncertainty is high about the project’s deliverables, resource needs, and work required.
And all this uncertainty means that a project is most likely to fail early in its life cycle.
Stakeholder influence in the project and its deliverables is highest early in the life cycle but diminishes as the project proceeds because the cost of incorporating changes increases the further the project is into its life cycle.
So one way of controlling unexpected project cost is to engage stakeholders early to prevent unnecessary and costly changes later in the project.
Product vs. Project Life Cycle Relationships
The product life cycle consists of generally sequential, non-overlapping product phases determined by the manufacturing and control need of the organization.
The last product lifecycle phase for a product is generally the product’s retirement.
Project life cycles occur in one or more phases of a product lifecycle. Care should be taken to distinguish the project life cycle from the product life cycle.
All projects have a purpose or objective, but in those cases where the objective is a service or result, there may be a life cycle for the service or result, not a product lifecycle.
Project phases are divisions within a project where extra control is needed to effectively manage the completion of a major deliverable.
Project phases are typically completed sequentially but can overlap in some project situations.
The high-level nature of project phases makes them an element of the project life cycle.
A project phase is not a Project Management Process Group.
The phase structure allows the project to be segmented into logical subsets for ease of management, planning, and control.
The number of phases, the need for phases, and the degree of control applied depend on the size, complexity, and potential impact of the project.
Regardless of the number of phases comprising a project, all phases have similar characteristics:
- When phases are sequential, the close of a phase ends with some form of transfer or hand-off of the work product produced as the phase deliverable.
This phase-end represents a natural point to reassess the effort underway and to change or terminate the project if necessary.
These points are referred to as phase exits, milestones, phase gates, decision gates, stage gates, or kill points.
- The work has a distinct focus that differs from any other phase. This often involves different organizations and different skill sets.
- The primary deliverable or objective of the phase requires an extra degree of control to be successfully achieved. The repetition of processes across all five Process Groups provides that additional degree of control and defines the boundaries of the phase.