Characteristics of the Project Life Cycle
The project life cycle defines the phases that connect the
beginning of a project to its end. For example, when an organization identifies
an opportunity to which it would like to respond, it will often authorize a
feasibility study to decide whether it should undertake the project. The project
life cycle definition can help the project manager clarify whether to treat the
feasibility study as the first project phase or as a separate, stand-alone
project. Where the outcome of such a preliminary effort is not clearly
identifiable, it is best to treat such efforts as a separate project. The phases
of a project life cycle are not the same as the Project Management Process
Groups described in detail in Chapter 3.
The transition from one phase to another within a project’s life
cycle generally involves, and is usually defined by, some form of technical
transfer or handoff. Deliverables from one phase are usually reviewed for
completeness and accuracy and approved before work starts on the next phase.
However, it is not uncommon for a phase to begin prior to the approval of the
previous phase’s deliverables, when the risks involved are deemed acceptable.
This practice of overlapping phases, normally done in sequence, is an example of
the application of the schedule compression technique called fast tracking.
There is no single best way to define an ideal project life cycle.
Some organizations have established policies that standardize all projects with
a single life cycle, while others allow the project management team to choose
the most appropriate life cycle for the team’s project. Further, industry common
practices will often lead to the use of a preferred life cycle within that
Project life cycles generally define:
What technical work to do in each phase (for example, in
which phase should the architect’s work be performed?)
When the deliverables are to be generated in each phase and
how each deliverable is reviewed, verified, and validated
Who is involved in each phase (for example, concurrent
engineering requires that the implementers be involved with requirements and
How to control and approve each phase.
Project life cycle descriptions can be very general or very
detailed. Highly detailed descriptions of life cycles can include forms, charts,
and checklists to provide structure and control.
Most project life cycles share a number of common characteristics:
Phases are generally sequential and are usually defined by
some form of technical information transfer or technical component handoff.
Cost and staffing levels are low at the start, peak during
the intermediate phases, and drop rapidly as the project draws to a conclusion.
Figure 2-1 illustrates this pattern.
Figure 2-1. Typical Project Cost and Staffing
Level Across the Project Life Cycle
The level of uncertainty is highest and, hence, risk of
failing to achieve the objectives is greatest at the start of the project. The
certainty of completion generally gets progressively better as the project
The ability of the stakeholders to influence the final
characteristics of the project’s product and the final cost of the project is
highest at the start, and gets progressively lower as the project continues. A
major contributor to this phenomenon is that the cost of changes and correcting
errors generally increases as the project continues.
Although many project life cycles have similar
phase names with similar deliverables, few life cycles are identical. Some can
have four or five phases, but others may have nine or more. Single application
areas are known to have significant variations. One organization’s software
development life cycle can have a single design phase, while another can have
separate phases for architectural and detailed design. Subprojects can also have
distinct project life cycles. For example, an architectural firm hired to design
a new office building is first involved in the owner’s definition phase while
doing the design, and in the owner’s implementation phase while supporting the
construction effort. The architect’s design project, however, will have its own
series of phases from conceptual development, through definition and
implementation, to closure. The architect can even treat designing the facility
and supporting the construction as separate projects, each with its own set of