2.2 Project Life Cycle Phases

Key Takeaways

  • The project life cycle consists of phases that a project passes through from start to finish, and phases can be sequential, overlapping, or iterative
  • Common phases include Initiating/Starting, Organizing and Preparing, Executing/Carrying Out Work, and Closing/Ending
  • Phase gates (also called stage gates, kill points, or decision points) are review checkpoints between phases where continuation decisions are made
  • Cost and staffing levels start low, peak during execution, and drop during closing
  • Risk and uncertainty are highest at the start and decrease as the project progresses through its life cycle
Last updated: March 2026

Project Life Cycle Phases

The project life cycle is the series of phases that a project passes through from its initiation to its closure. Understanding the life cycle helps project managers structure work, allocate resources, and make informed decisions at each stage.

Generic Project Life Cycle

While specific life cycles vary by industry and organization, most projects follow a generic pattern:

PhaseActivitiesKey Outputs
Starting the ProjectDefine purpose, feasibility, high-level scopeProject charter, stakeholder register
Organizing and PreparingDevelop detailed plans, assemble teamProject management plan, WBS
Carrying Out Project WorkExecute plans, produce deliverablesDeliverables, performance data
Ending the ProjectVerify completion, archive documentsFinal product, lessons learned

Phase Relationships

Project phases can be organized in different ways:

Sequential Relationship

Each phase starts only after the previous phase is complete. This is the most conservative approach and reduces uncertainty but takes the longest.

Overlapping (Fast-Tracking) Relationship

A phase starts before the previous phase is complete. This compresses the schedule but increases risk because later phases start with incomplete information from earlier phases.

Iterative Relationship

Phases repeat in cycles, with each iteration producing a more refined version of the deliverable. This is common in agile and adaptive approaches.


Phase Gates (Stage Gates)

A phase gate is a review at the end of a phase where a decision is made about whether to continue to the next phase, continue with modifications, end the project, or remain in the current phase.

Phase Gate Decisions

DecisionDescription
GoContinue to the next phase as planned
Go with modificationsContinue but adjust plans, budget, or scope
KillTerminate the project
HoldRemain in the current phase for more analysis

Other Names for Phase Gates

  • Stage gates
  • Kill points
  • Decision points
  • Phase exits
  • Milestone reviews
  • Toll gates

How Project Characteristics Change Over the Life Cycle

Understanding how key project variables change across the life cycle is critical for exam questions:

Cost and Staffing Levels

  • Start low during initiating
  • Build gradually during planning
  • Peak during executing
  • Drop rapidly during closing

Risk and Uncertainty

  • Highest at the start of the project (most unknowns)
  • Decrease progressively as decisions are made and work is completed
  • Risk cannot be eliminated entirely until the project is complete

Stakeholder Influence

  • Greatest at the start when major decisions are still open
  • Decreases as the project progresses because the cost of changes increases

Cost of Changes

  • Lowest at the beginning when changes are easy to incorporate
  • Increases significantly as the project progresses
  • Making changes during execution is far more expensive than during planning

Critical Exam Concept: The relationship between stakeholder influence and cost of changes is inversely proportional. When stakeholders have the most influence (early), changes are cheapest. When changes are most expensive (late), stakeholders have less ability to influence.


Predictive vs. Adaptive Life Cycles

CharacteristicPredictive Life CycleAdaptive Life Cycle
PlanningDetailed upfrontProgressive elaboration
RequirementsDefined early, stableEvolving, refined iteratively
DeliverablesSingle delivery at endIncremental/iterative deliveries
ChangeControlled through formal processWelcomed and expected
FeedbackAt phase gatesContinuous
RiskManaged through planningManaged through iterations
Best ForWell-understood projectsHigh uncertainty, evolving needs
Test Your Knowledge

At which point in the project life cycle are risk and uncertainty typically HIGHEST?

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D
Test Your Knowledge

What is a phase gate?

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Test Your Knowledge

When is the cost of making changes to a project typically the LOWEST?

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D