Planning Waves (PMI)

1. Work Breakdown Structure (WBS) Recap

  • Definition:
    A deliverable-oriented hierarchical decomposition of project scope into smaller, manageable elements.
    ➝ Goal: Ensure all work is captured and no unnecessary work is included.

  • Structure:
    • Level 1: Project / Final Deliverable
    • Level 2: Major Deliverables or Phases
    • Level 3+: Sub-deliverables → Work Packages
    • Lowest Level: Work Package = tangible, schedulable, assignable unit.
  • Functions:
    • Provides framework for scope definition, scheduling, cost estimating, risk management, and reporting.
    • Enables progressive decomposition—breaking work down “one bite at a time.”

2. Planning Waves (Rolling Wave Planning)

  • Definition:
    A progressive elaboration technique where near-term work is planned in detail, while future work is kept at a higher level until closer in time.
    • Short-term: Detailed WBS decomposition.
    • Long-term: High-level WBS placeholders refined later.
  • Why use planning waves?
    • Large or long-duration projects cannot be fully detailed at the start.
    • Helps manage uncertainty and complexity.
    • Balances flexibility with control.
    • Allows project managers to adapt as more information becomes available.

3. WBS Life-Cycle Considerations

  • Level of Detail Depends On:
    • Project size and complexity.
    • Risks associated with deliverables.
    • Project manager’s need for control.
  • Different Levels Across Project:
    • Some parts of WBS may be highly detailed (near-term work).
    • Other parts remain summarized (future work, pending clarity).
  • Short-duration projects:
    • Full decomposition possible upfront.
  • Long-duration projects:
    • Decomposition delayed for some deliverables until later in the life cycle.

4. Risk and Planning Waves

  • WBS and Risk Management:
    • High-risk areas → need greater detail early (better assumptions, estimates, and control).
    • WBS supports linking risks to specific deliverables for targeted mitigation.
  • Rolling Wave + Risk:
    • Allows project managers to refine scope in risky areas when more data is available.
    • Reduces waste from over-planning uncertain tasks.

5. Practical Guidelines

When creating WBS with planning waves in mind:

  1. Start high-level: Identify the final deliverables.
  2. Detail near-term work: Break down immediate phases into work packages.
  3. Leave future work flexible: Keep as high-level placeholders until execution nears.
  4. Iteratively refine: Update decomposition as scope, risk, and requirements become clearer.
  5. Balance detail vs usability: Too much detail = overhead; too little = loss of control.

6. Example – Rolling Wave WBS

Imagine a 3-year IT program:

  • Near-term (Year 1):
    • Detailed work packages for requirements gathering, architecture, prototypes.
  • Mid-term (Year 2):
    • High-level WBS entries like “System Development” → later decomposed into module builds.
  • Long-term (Year 3):
    • Placeholder “Deployment & Support” → later detailed into training, rollout, stabilization.
graph TD
  P["Project (Level 1)"]

  %% Wave 1 - Near Term (Detailed)
  P --> W1["1.0 Requirements & Design (Near-Term, Detailed)"]
  W1 --> W1_1["1.1 Requirements Gathering"]
  W1 --> W1_2["1.2 System Architecture"]
  W1 --> W1_3["1.3 Prototype Development"]

  %% Wave 2 - Mid Term (Medium Detail)
  P --> W2["2.0 Development (Mid-Term, Medium Detail)"]
  W2 --> W2_1["2.1 Module A"]
  W2 --> W2_2["2.2 Module B"]
  %% note: not fully decomposed yet

  %% Wave 3 - Long Term (High Level / Placeholder)
  P --> W3["3.0 Deployment & Support (Long-Term, High-Level)"]
  %% Placeholder – decomposition will come later

Summary:

  • The WBS is the backbone of project planning and integrates scope, cost, schedule, and risk.
  • Planning waves (rolling wave planning) recognize that not all future work can be fully decomposed at the start.
  • Near-term = detailed, future = high-level, refined later.
  • This approach increases adaptability, reduces planning waste, and helps manage uncertainty in complex, long-duration projects.

Source

Woodward, H. “Project Management Institute practice standard for work breakdown structures. 2001, Newton Square: Project Management Institute.”

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