Project life cycles in detail

A project life cycle is a collection of project phases, generally sequential, that takes a project from its start to its end. The names and number of phases depend on the needs of the organisation and the nature of the project. It gives a framework for management, approval and control, with each phase ending in a deliverable and a review (phase gate).

General features

• Cost and staffing are low at the start, peak during execution, and fall rapidly at close.
• Risk and uncertainty are highest at the start, and decrease as the project progresses.
• Stakeholders' ability to influence the result is greatest at the start; the cost of changes rises over time.

Level of
effort
  |        ____
  |       /    \
  |   ___/      \___
  |__/              \__
  +---------------------> time
  Start  Org  Execute  Close

Representative project life cycle (Schwalbe / PMBOK)

Four phases for a generic project:

1. Concept (initiation): develop a brief proposal, high-level cost and time estimates, do a feasibility study, and write the business case and charter.
2. Development (planning): prepare the detailed project plan: WBS, schedule, budget, resources, risk and communication plans.
3. Implementation (execution): deliver the work, build the product, monitor and control progress, quality and changes.
4. Close-out: complete the work, get customer acceptance, hand over, release resources, document lessons learned.

IT example (software)

Types

• Predictive (waterfall): scope, time and cost fixed early.
• Iterative/incremental: product built in repeated cycles.
• Adaptive (agile): scope changes with feedback.

Life cycles help in controlling progress, using phase-end reviews to decide whether to continue.